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The missing link in linear alkylbenzenesulfonate surfactant degradation : 4-sulfoacetophenone as a transient intermediate in the degradation of 3-(4-sulfophenyl) butyrate by comamonas testosteroni KF-1
Schleheck, David; Netzer, Frederick von; Fleischmann, Thomas; Rentsch, Daniel; Huhn, Thomas; Cook, Alasdair M.; Kohler, Hans-Peter E.
Biodegradation of the laundry surfactant linear alkylbenzenesulfonate (LAS) involves complex bacterial communities. The known heterotrophic community has two tiers. First, all LAS congeners are oxygenated and oxidized to about 50 sulfophenylcarboxylates (SPC). Second, the SPCs are mineralized. Comamonas testosteroni KF-1 mineralizes 3-(4-sulfophenyl)butyrate (3-C4-SPC). During growth of strain KF-1 with 3-C4-SPC, two transient intermediates were detected in the culture medium. One intermediat...
Protein quantification by MALDI-selected reaction monitoring mass spectrometry using sulfonate derivatized peptides.
Lesur, Antoine; Varesio, Emmanuel; Hopfgartner, Gérard
The feasibility of protein absolute quantification with matrix-assisted laser desorption/ionization (MALDI) using the selected reaction monitoring (SRM) acquisition mode on a triple quadrupole linear ion trap mass spectrometer (QqQ(LIT)) equipped with a high-frequency laser is demonstrated. A therapeutic human monoclonal antibody (mAb) was used as a model protein, and four tryptic peptides generated by fast tryptic digestion were selected as quantification surrogates. MALDI produces mostly singly charged peptides which hardly fragment under low-energy collision-induced dissociation (CID), and therefore the benefits of using 4-sulfophenyl isothiocyanate (SPITC) as a fragmentation enhancer derivatization agent were evaluated. Despite a moderate impact on the sensitivity, the N-terminus sulfonated peptides generate nearly complete y-ion ladders when native peptides produce few fragments. This aspect provides an alternative SRM transition set for each peptide. As a consequence, SRM transitions selectivity can be tuned more easily for peptide quantitation in complex matrices when monitoring several SRM transitions. From a quantitative point of view, the signal response depending on mAb concentration was found to be linear over 2.5 orders of magnitude for the most sensitive peptide, allowing precise and accurate measurement by MALDI-SRM/MS. PMID:20481516
Targeting Antiapoptotic Bcl-2 Family Members with Cell-Permeable BH3 Peptides Induces Apoptosis Signaling, Death in Head, Neck Squamous Cell Carcinoma Cells
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Rongxiu Li
Full Text Available Head, neck squamous cell carcinomas (HNSCCs are frequently characterized by chemotherapy, radiation resistance, by overexpression of Bcl-XL, an antiapoptotic member of the Bcl-2 protein family. In this report, we examined whether cell-permeable peptides derived from the BH3 domains of proapoptotic Bax, Bad, or Bak could be used to target Bcl-XL and/or Bcl-2 in HNSCC cells, induce apoptotic death in these cells. To render the peptides cell-permeable, Antennapedia (Ant or polyarginine (R8 peptide transduction domain was fused to the amino termini. Fluorescence microscopy of peptide-treated HNSCC cells revealed that the BH3 peptides colocalized with mitochondria, the site of Bcl-XL, Bcl-2 expression. By contrast, a mutant peptide (BaxE BH3 that cannot bind Bcl-XL or Bcl-2 was diffusely localized throughout the cytoplasm. Treatment of three HNSCC cell lines (1483, UM-22A, UM-22B with the wild-type BH3 peptides resulted in loss of viability, induction of apoptosis, as assessed by 3-(4,5-dimethythiazol-2yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H-tetrazolium (MTS assays, annexin V staining. In general, Ant-conjugated peptides were more potent than R8-conjugated peptides, Bad BH3 peptide was typically more potent than Bax BH3 or Bak BH3. Treatment of purified HNSCC mitochondria with BH3 peptides resulted in robust release of cytochrome c. Thus, the relative apoptosis resistance of HNSCC cells is not due to a deficit in this step of the intrinsic, mitochondrialmediated apoptosis pathway. We conclude that cellpermeable BH3 peptides can be used to target Bcl-XL and/or Bcl-2 in HNSCC, that targeting of these proteins may have therapeutic value in the treatment of this disease.
Glucagonlike Peptide 2 Analogue Teduglutide
Chaturvedi, Lakshmi S.; Basson, Marc D.
IMPORTANCE Short bowel syndrome occurs when a shortened intestine cannot absorb sufficient nutrients or fluids. Teduglutide is a recombinant analogue of human glucagonlike peptide 2 that reduces dependence on parenteral nutrition in patients with short bowel syndrome by promoting enterocytic proliferation, increasing the absorptive surface area. However, enterocyte function depends not only on the number of cells that are present but also on differentiated features that facilitate nutrient absorption and digestion. OBJECTIVE To test the hypothesis that teduglutide impairs human intestinal epithelial differentiation. DESIGN AND SETTING We investigated the effects of teduglutide in the modulation of proliferation and differentiation in human Caco-2 intestinal epithelial cells at a basic science laboratory. This was an in vitro study using Caco-2 cells, a human-derived intestinal epithelial cell line commonly used to model enterocytic biology. EXPOSURE Cells were exposed to teduglutide or vehicle control. MAINOUTCOMESAND MEASURES We analyzed the cell cycle by bromodeoxyuridine incorporation or propidium iodide staining and flow cytometry and measured cell proliferation by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. We used quantitative reverse transcription–polymerase chain reaction to assay the expression of the enterocytic differentiation markers villin, sucrase-isomaltase, glucose transporter 2 (GLUT2), and dipeptidyl peptidase 4 (DPP-4), as well as that of the putative differentiation signals schlafen 12 (SLFN12) and caudal-related homeobox intestine-specific transcription factor (Cdx2). Villin promoter activity was measured by a luciferase-based assay. RESULTS The MTS assay demonstrated that teduglutide increased cell numbers by a mean (SD) of 10% (2%) over untreated controls at a maximal 500nM (n = 6, P < .05). Teduglutide increased bromodeoxyuridine-positive cells vs untreated controls by a mean (SD
Czech Academy of Sciences Publication Activity Database
Niederhafner, Petr; Šebestík, Jaroslav; Ježek, Jan
Roč. 11, - (2005), 757-788. ISSN 1075-2617 R&D Projects: GA ČR(CZ) GA203/03/1362 Institutional research plan: CEZ:AV0Z40550506 Keywords : multiple antigen peptides * peptide dendrimers * synthetic vaccine * multipleantigenic peptides Subject RIV: CC - Organic Chemistry Impact factor: 1.803, year: 2005
DEFF Research Database (Denmark)
Nielsen, Carsten Uhd; Brodin, Birger; Jørgensen, Flemming Steen;
Peptide transporters are epithelial solute carriers. Their functional role has been characterised in the small intestine and proximal tubules, where they are involved in absorption of dietary peptides and peptide reabsorption, respectively. Currently, two peptide transporters, PepT1 and PepT2, wh...
DEFF Research Database (Denmark)
Hansen, Paul Robert
To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined.......To produce antibodies against synthetic peptides it is necessary to couple them to a protein carrier. This chapter provides a nonspecialist overview of peptide-carrier conjugation. Furthermore, a protocol for coupling cysteine-containing peptides to bovine serum albumin is outlined....
Proteome analysis of vaccinia virus IHD-W-infected HEK 293 cells with 2-dimensional gel electrophoresis and MALDI-PSD-TOF MS of on solid phase support N-terminally sulfonated peptides
Directory of Open Access Journals (Sweden)
Bartel Sebastian
Full Text Available Abstract Background Despite the successful eradication of smallpox by the WHO-led vaccination programme, pox virus infections remain a considerable health threat. The possible use of smallpox as a bioterrorism agent as well as the continuous occurrence of zoonotic pox virus infections document the relevance to deepen the understanding for virus host interactions. Since the permissiveness of pox infections is independent of hosts surface receptors, but correlates with the ability of the virus to infiltrate the antiviral host response, it directly depends on the hosts proteome set. In this report the proteome of HEK293 cells infected with Vaccinia Virus strain IHD-W was analyzed by 2-dimensional gel electrophoresis and MALDI-PSD-TOF MS in a bottom-up approach. Results The cellular and viral proteomes of VACV IHD-W infected HEK293 cells, UV-inactivated VACV IHD-W-treated as well as non-infected cells were compared. Derivatization of peptides with 4-sulfophenyl isothiocyanate (SPITC carried out on ZipTipμ-C18 columns enabled protein identification via the peptides' primary sequence, providing improved s/n ratios as well as signal intensities of the PSD spectra. The expression of more than 24 human proteins was modulated by the viral infection. Effects of UV-inactivated and infectious viruses on the hosts' proteome concerning energy metabolism and proteins associated with gene expression and protein-biosynthesis were quite similar. These effects might therefore be attributed to virus entry and virion proteins. However, the modulation of proteins involved in apoptosis was clearly correlated to infectious viruses. Conclusions The proteome analysis of infected cells provides insight into apoptosis modulation, regulation of cellular gene expression and the regulation of energy metabolism. The confidence of protein identifications was clearly improved by the peptides' derivatization with SPITC on a solid phase support. Some of the identified proteins
U.S. Department of Health & Human Services — PeptideAtlas is a multi-organism, publicly accessible compendium of peptides identified in a large set of tandem mass spectrometry proteomics experiments. Mass...
DEFF Research Database (Denmark)
Buchmann, Kurt
Antimikrobielle Peptider har hos mere primitive dyr en vigtig funktion i organismernes immunforsvar Udgivelsesdato: 1. februar......Antimikrobielle Peptider har hos mere primitive dyr en vigtig funktion i organismernes immunforsvar Udgivelsesdato: 1. februar...
DEFF Research Database (Denmark)
A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....
DEFF Research Database (Denmark)
A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....
DEFF Research Database (Denmark)
A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....
DEFF Research Database (Denmark)
A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....
Antimicrobial Peptides in 2014
Directory of Open Access Journals (Sweden)
Guangshun Wang
Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.
PH dependent adhesive peptides
Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan
A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.
[Plant signaling peptides. Cysteine-rich peptides].
Ostrowski, Maciej; Kowalczyk, Stanisław
Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding. Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function. The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group. There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation. PMID:26281357
Wiśniewska, Justyna; Trejgell, Alina; Tretyn, Andrzej
Biochemical and genetic studies have identified peptides that play crucial roles in plant growth and development, including defence mechanisms in response to wounding by pests, the control of cell division and expansion, and pollen self-incompatibility. The first two signalling peptides to be described in plants were tomato systemin and phytosulfokine (PSK). There is also biochemical evidence that natriuretic peptide-like molecules, immunologically-relatedt o those found ...
Polycyclic peptide therapeutics.
Baeriswyl, Vanessa; Heinis, Christian
Owing to their excellent binding properties, high stability, and low off-target toxicity, polycyclic peptides are an attractive molecule format for the development of therapeutics. Currently, only a handful of polycyclic peptides are used in the clinic; examples include the antibiotic vancomycin, the anticancer drugs actinomycin D and romidepsin, and the analgesic agent ziconotide. All clinically used polycyclic peptide drugs are derived from natural sources, such as soil bacteria in the case of vancomycin, actinomycin D and romidepsin, or the venom of a fish-hunting coil snail in the case of ziconotide. Unfortunately, nature provides peptide macrocyclic ligands for only a small fraction of therapeutic targets. For the generation of ligands of targets of choice, researchers have inserted artificial binding sites into natural polycyclic peptide scaffolds, such as cystine knot proteins, using rational design or directed evolution approaches. More recently, large combinatorial libraries of genetically encoded bicyclic peptides have been generated de novo and screened by phage display. In this Minireview, the properties of existing polycyclic peptide drugs are discussed and related to their interesting molecular architectures. Furthermore, technologies that allow the development of unnatural polycyclic peptide ligands are discussed. Recent application of these technologies has generated promising results, suggesting that polycyclic peptide therapeutics could potentially be developed for a broad range of diseases. PMID:23355488
C-peptide ... the test depends on the reason for the C-peptide measurement. Ask your health care provider if ... C-peptide is measured to tell the difference between insulin produced by the body and insulin injected ...
DEFF Research Database (Denmark)
A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a...
DEFF Research Database (Denmark)
Koch, T.; Næsby, M.; Wittung, P.; Jørgensen, M.; Larsson, C.; Buchardt, O.; Stanly, C.J.; Norden, B.; Nielsen, P.E.; Ørum, H.
Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields.......Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields....
Descriptors for antimicrobial peptides
DEFF Research Database (Denmark)
Jenssen, Håvard
Introduction: A frightening increase in the number of isolated multidrug resistant bacterial strains linked to the decline in novel antimicrobial drugs entering the market is a great cause for concern. Cationic antimicrobial peptides (AMPs) have lately been introduced as a potential new class of...... antimicrobial drugs, and computational methods utilizing molecular descriptors can significantly accelerate the development of new peptide drug candidates. Areas covered: This paper gives a broad overview of peptide and amino-acid scale descriptors available for AMP modeling and highlights which of these are...
DEFF Research Database (Denmark)
Koch, T.; Næsby, M.; Wittung, P.;
Radioactive labelling of PNA has been performed try linking a peptide segment to the PNA which is substrate for protein kinase A. The enzymatic phosphorylation proceeds in almost quantitative yields....
Directory of Open Access Journals (Sweden)
Full Text Available Tumor-homing peptides can be used to deliver drugs into tumors. Phage library screening in live mice has recently identified homing peptides that specifically recognize the endothelium of tumor vessels, extravasate, and penetrate deep into the extravascular tumor tissue. The prototypic peptide of this class, iRGD (CRGDKGPDC, contains the integrin-binding RGD motif. RGD mediates tumor homing through binding to αv integrins, which are selectively expressed on various cells in tumors, including tumor endothelial cells. The tumor-penetrating properties of iRGD are mediated by a second sequence motif, R/KXXR/K. This C-end Rule (or CendR motif is active only when the second basic residue is exposed at the C-terminus of the peptide. Proteolytic processing of iRGD in tumors activates the cryptic CendR motif, which then binds to neuropilin-1 activating an endocytic bulk transport pathway through tumor tissue. Phage screening has also yielded tumor-penetrating peptides that function like iRGD in activating the CendR pathway, but bind to a different primary receptor. Moreover, novel tumor-homing peptides can be constructed from tumor-homing motifs, CendR elements and protease cleavage sites. Pathologies other than tumors can be targeted with tissue-penetrating peptides, and the primary receptor can also be a vascular "zip code" of a normal tissue. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. The tumor-penetrating peptides are capable of taking a payload deep into tumor tissue in mice, and they also penetrate into human tumors ex vivo. Targeting with these peptides specifically increases the accumulation in tumors of a variety of drugs and contrast agents, such as doxorubicin, antibodies and nanoparticle-based compounds. Remarkably the drug to be targeted does not have to be coupled to the peptide; the bulk transport system activated by the peptide sweeps along any compound that is
Introduction to Peptide Synthesis
Stawikowski, Maciej; Fields, Gregg B.
A number of synthetic peptides are significant commercial or pharmaceutical products, ranging from the dipeptide sugar-substitute aspartame to clinically used hormones, such as oxytocin, adrenocorticotropic hormone, and calcitonin. This unit provides an overview of the field of synthetic peptides and proteins. It discusses selecting the solid support and common coupling reagents. Additional information is provided regarding common side reactions and synthesizing modified residues.
Antimicrobial Peptides from Plants
Tam, James P.; Wang, Shujing; Wong, Ka H.; Tan, Wei Liang
Plant antimicrobial peptides (AMPs) have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs) of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic), lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms. PMID:26580629
Antimicrobial Peptides from Plants
Directory of Open Access Journals (Sweden)
James P. Tam
Full Text Available Plant antimicrobial peptides (AMPs have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic, lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms.
Electromembrane extraction of peptides.
Balchen, Marte; Reubsaet, Léon; Pedersen-Bjergaard, Stig
Rapid extraction of eight different peptides using electromembrane extraction (EME) was demonstrated for the first time. During an extraction time of 5 min, the model peptides migrated from a 500 microL aqueous acidic sample solution, through a thin supported liquid membrane (SLM) of an organic liquid sustained in the pores in the wall of a porous hollow fiber, and into a 25 microL aqueous acidic acceptor solution present inside the lumen of the hollow fiber. The driving force of the extraction was a 50 V potential sustained across the SLM, with the positive electrode in the sample and the negative electrode in the acceptor solution. The nature and the composition of the SLM were highly important for the EME process, and a mixture of 1-octanol and 15% di(2-ethylhexyl) phosphate was found to work properly. Using 1mM HCl as background electrolyte in the sample and 100 mM HCl in the acceptor solution, and agitation at 1050 rpm, enrichment up to 11 times was achieved. Recoveries were found to be dependent on the structure of the peptide, indicating that the polarity and the number of ionized groups were important parameters affecting the extraction efficiency. The experimental findings suggested that electromembrane extraction of peptides is possible and may be a valuable tool for future extraction of peptides. PMID:18479691
Synthetic antibiofilm peptides.
de la Fuente-Núñez, César; Cardoso, Marlon Henrique; de Souza Cândido, Elizabete; Franco, Octavio Luiz; Hancock, Robert E W
Bacteria predominantly exist as multicellular aggregates known as biofilms that are associated with at least two thirds of all infections and exhibit increased adaptive resistance to conventional antibiotic therapies. Therefore, biofilms are major contributors to the global health problem of antibiotic resistance, and novel approaches to counter them are urgently needed. Small molecules of the innate immune system called host defense peptides (HDPs) have emerged as promising templates for the design of potent, broad-spectrum antibiofilm agents. Here, we review recent developments in the new field of synthetic antibiofilm peptides, including mechanistic insights, synergistic interactions with available antibiotics, and their potential as novel antimicrobials against persistent infections caused by biofilms. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26724202
Biomimetic peptide nanosensors.
Cui, Yue; Kim, Sang N; Naik, Rajesh R; McAlpine, Michael C
The development of a miniaturized sensing platform tailored for sensitive and selective detection of a variety of biochemical analytes could offer transformative fundamental and technological opportunities. Due to their high surface-to-volume ratios, nanoscale materials are extremely sensitive sensors. Likewise, peptides represent robust substrates for selective recognition due to the potential for broad chemical diversity within their relatively compact size. Here we explore the possibilities of linking peptides to nanosensors for the selective detection of biochemical targets. Such systems raise a number of interesting fundamental challenges: What are the peptide sequences, and how can rational design be used to derive selective binders? What nanomaterials should be used, and what are some strategies for assembling hybrid nanosensors? What role does molecular modeling play in elucidating response mechanisms? What is the resulting performance of these sensors, in terms of sensitivity, selectivity, and response time? What are some potential applications? This Account will highlight our early attempts to address these research challenges. Specifically, we use natural peptide sequences or sequences identified from phage display as capture elements. The sensors are based on a variety of nanomaterials including nanowires, graphene, and carbon nanotubes. We couple peptides to the nanomaterial surfaces via traditional surface functionalization methods or self-assembly. Molecular modeling provides detailed insights into the hybrid nanostructure, as well as the sensor detection mechanisms. The peptide nanosensors can distinguish chemically camouflaged mixtures of vapors and detect chemical warfare agents with sensitivities as low as parts-per-billion levels. Finally, we anticipate future uses of this technology in biomedicine: for example, devices based on these sensors could detect disease from the molecular components in human breath. Overall, these results provide a
Therapeutic HIV Peptide Vaccine
DEFF Research Database (Denmark)
Fomsgaard, Anders
Therapeutic vaccines aim to control chronic HIV infection and eliminate the need for lifelong antiretroviral therapy (ART). Therapeutic HIV vaccine is being pursued as part of a functional cure for HIV/AIDS. We have outlined a basic protocol for inducing new T cell immunity during chronic HIV-1...... infection directed to subdominant conserved HIV-1 epitopes restricted to frequent HLA supertypes. The rationale for selecting HIV peptides and adjuvants are provided. Peptide subunit vaccines are regarded as safe due to the simplicity, quality, purity, and low toxicity. The caveat is reduced immunogenicity...
Cationic Antimicrobial Peptide Cytotoxicity
Laverty, Garry; Gilmore, Brendan
Fluorescence microscopy serves as a valuable tool for assessing the structural integrity and viability of eukaryotic cells. Through the use of calcein AM and the DNA stain 4,6-diamidino-2 phenylindole (DAPI), cell viability and membrane integrity can be qualified. Our group has previously shown the ultra-short cationic antimicrobial peptide H-OOWW-NH2; the amphibian derived 27-mer peptide Maximin-4and the ultra-short lipopeptide C12-OOWW-NH2 to be effective against a range of bacterial biofil...
Biosynthesis of cardiac natriuretic peptides
DEFF Research Database (Denmark)
Goetze, Jens Peter
Cardiac-derived peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac natriuretic peptides and their molecular precursors as useful markers of heart disease. In contrast to the clinical applications, the biogenesis of cardiac p...... competent endocrine cells. The structurally related atrial natriuretic peptide will be mentioned where appropriate, whereas C-type natriuretic peptide will not be considered as a cardiac peptide of relevance in mammalian physiology....... characterized. An ongoing characterization of the molecular heterogeneity will help appreciate the biosynthetic capacity of the endocrine heart and could introduce new diagnostic possibilities. Notably, different biosynthetic products may not be equal markers of the same pathophysiological processes. An...... inefficient post-translational prohormone maturation will also affect the biology of the cardiac natriuretic peptide system. This review aims at summarizing the myocardial synthesis of natriuretic peptides focusing on B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly...
Biosynthesis of cardiac natriuretic peptides
DEFF Research Database (Denmark)
Goetze, Jens Peter
Cardiac-derived peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac natriuretic peptides and their molecular precursors as useful markers of heart disease. In contrast to the clinical applications, the biogenesis of cardiac...... inefficient post-translational prohormone maturation will also affect the biology of the cardiac natriuretic peptide system. This review aims at summarizing the myocardial synthesis of natriuretic peptides focusing on B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly...... competent endocrine cells. The structurally related atrial natriuretic peptide will be mentioned where appropriate, whereas C-type natriuretic peptide will not be considered as a cardiac peptide of relevance in mammalian physiology....
Biochemical functionalization of peptide nanotubes with phage displayed peptides
Swaminathan, Swathi; Cui, Yue
The development of a general approach for the biochemical functionalization of peptide nanotubes (PNTs) could open up existing opportunities in both fundamental studies as well as a variety of applications. PNTs are spontaneously assembled organic nanostructures made from peptides. Phage display has emerged as a powerful approach for identifying selective peptide binding motifs. Here, we demonstrate for the first time the biochemical functionalization of PNTs via peptides identified from a phage display peptide library. The phage-displayed peptides are shown to recognize PNTs. These advances further allow for the development of bifunctional peptides for the capture of bacteria and the self-assembly of silver particles onto PNTs. We anticipate that these results could provide significant opportunities for using PNTs in both fundamental studies and practical applications, including sensors and biosensors nanoelectronics, energy storage devices, drug delivery, and tissue engineering.
Peptide iodination on phenylalanine residues
International Nuclear Information System (INIS)
Peptide labelling with radioactive isotopes is always a compromise between peptide chemistry, labelling chemistry, and biological receptor tolerance. Therefore new ways for isotope introduction are always useful. The present contribution describes the introduction of iodine isotopes onto synthetic polypeptides by means of the Gattermann/ Sandmeyer reactions. Peptides containing the nitrophenylalanyl residue are reduced to the corresponding aminophenylalanyl, diazolized to the diazonium phenylalanyl peptide and converted to the iodophenylalanyl peptide in the presence of copper. Two examples are presented: angiotensin II and enkephalin. In both cases, the iodophenylalanyl residue is well accepted by the biological target. (author). 13 refs.; 4 figs
Radiolabelled peptides for oncological diagnosis
Energy Technology Data Exchange (ETDEWEB)
Laverman, Peter; Boerman, Otto C.; Oyen, Wim J.G. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine, Nijmegen (Netherlands); Sosabowski, Jane K. [Queen Mary University of London, Centre for Molecular Oncology, Barts Cancer Institute, London (United Kingdom)
Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The {sup 111}In-labelled somatostatin analogue octreotide (OctreoScan trademark) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours. (orig.)
Directory of Open Access Journals (Sweden)
Mehrzad Sadredinamin
Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.
Antimicrobial peptides in crustaceans
RD Rosa; MA Barracco
Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs) are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP fam...
La Villa, G; Lazzeri, C; Fronzaroli, C; Franchi, F; Gentilini, P
Brain natriuretic peptide (BNP) is a cardiac hormone with a spectrum of activities quite similar to those of atrial natriuretic peptide (ANP), including diuretic, natriuretic, hypotensive and smooth muscle relaxant activities. These effects are due to the stimulation of guanylate cyclase-linked natriuretic peptide receptors, leading to an increase in cyclic GMP concentration in target cells. BNP has a lower affinity than ANP for C (clearance) receptors, and is less susceptible to degradation by neutral endopeptidase-24.11, resulting in a longer half-life. In the kidney, BNP increases the glomerular filtration rate and inhibits sodium reabsorption in the distal tubule. It also inhibits the release of renin and aldosterone. Unlike ANP, produced by the atria, BNP is mainly synthesized and released into circulation by the left ventricle and is therefore influenced by stimuli involving this cardiac chamber, such as an increase in arterial pressure, left ventricular hypertrophy and dilation. Plasma BNP levels are very low in healthy subjects, and respond modestly, although significantly to physiological stimuli such as changes in posture or sodium intake. In contrast, plasma BNP concentrations increase in disease states such as cirrhosis with ascites, hypertension, chronic renal failure, acute myocardial infarction and congestive heart failure. In the latter condition, plasma BNP concentration is a reliable prognostic index. Evidence obtained by administering BNP to healthy subjects and hypertensive patients suggests that BNP, at physiological and pathophysiological plasma concentrations, markedly influences cardiovascular homeostasis, mainly due to its effects on sodium excretion and the renin-aldosterone axis. PMID:8718658
Accurate Peptide Fragment Mass Analysis: Multiplexed Peptide Identification and Quantification
Weisbrod, Chad R.; Eng, Jimmy K.; Hoopmann, Michael R.; Baker, Tahmina; Bruce, James E.
FT All Reaction Monitoring (FT-ARM) is a novel approach for the identification and quantification of peptides that relies upon the selectivity of high mass accuracy data and the specificity of peptide fragmentation patterns. An FT-ARM experiment involves continuous, data-independent, high mass accuracy MS/MS acquisition spanning a defined m/z range. Custom software was developed to search peptides against the multiplexed fragmentation spectra by comparing theoretical or empirical fragment ion...
NCAM Mimetic Peptides: An Update
DEFF Research Database (Denmark)
Berezin, Vladimir; Bock, Elisabeth
pharmacological tools interfering with NCAM functions. Recent progress in our understanding of the structural basis of NCAM-mediated cell adhesion and signaling has allowed a structure-based design of NCAM mimetic peptides. Using this approach a number of peptides termed P2, P1-B, P-3-DE and P-3-G, whose...... sequences contain one or several NCAM homophilic binding sites involved in NCAM binding to itself, have been identified. By means of NMR titration analysis and molecular modeling a number of peptides derived from NCAM and targeting NCAM heterophilic ligands such as the fibroblast growth factor receptor and...... heparan sulfate proteoglycans (HSPG) have been identified. The FGL, dekaCAM, FRM/EncaminA, BCL, EncaminC and EncaminE peptides all target the FGF receptor whereas the heparin binding peptide HBP targets HSPG. Moreover, a number of NCAM binding peptides have been identified employing screening of...
Deutsch, Eric W.
PeptideAtlas is a multi-species compendium of peptides observed with tandem mass spectrometry methods. Raw mass spectrometer output files are collected from the community and reprocessed through a uniform analysis and validation pipeline that continues to advance. The results are loaded into a database and the information derived from the raw data is returned to the community via several web-based data exploration tools. The PeptideAtlas resource is useful for experiment planning, improving g...
Human Antimicrobial Peptides and Proteins
Guangshun Wang
As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified ...
Improving Peptide Applications Using Nanotechnology.
Narayanaswamy, Radhika; Wang, Tao; Torchilin, Vladimir P
Peptides are being successfully used in various fields including therapy and drug delivery. With advancement in nanotechnology and targeted delivery carrier systems, suitable modification of peptides has enabled achievement of many desirable goals over-riding some of the major disadvantages associated with the delivery of peptides in vivo. Conjugation or physical encapsulation of peptides to various nanocarriers, such as liposomes, micelles and solid-lipid nanoparticles, has improved their in vivo performance multi-fold. The amenability of peptides to modification in chemistry and functionalization with suitable nanocarriers are very relevant aspects in their use and have led to the use of 'smart' nanoparticles with suitable linker chemistries that favor peptide targeting or release at the desired sites, minimizing off-target effects. This review focuses on how nanotechnology has been used to improve the number of peptide applications. The paper also focuses on the chemistry behind peptide conjugation to nanocarriers, the commonly employed linker chemistries and the several improvements that have already been achieved in the areas of peptide use with the help of nanotechnology. PMID:26279082
Peptides that influence membrane topology
Wong, Gerard C. L.
We examine the mechanism of a range of polypeptides that influence membrane topology, including antimicrobial peptides, cell penetrating peptides, viral fusion peptides, and apoptosis proteins, and show how a combination of geometry, coordination chemistry, and soft matter physics can be used to approach a unified understanding. We will also show how such peptides can impact biomedical problems such as auto-immune diseases (psoriasis, lupus), infectious diseases (viral and bacterial infections), and mitochondrial pathologies (under-regulated apoptosis leads to neurodegenerative diseases whereas over-regulated apoptosis leads to cancer.)
Pihl, Tina H; Illigen, Kristin E; Houen, Gunnar
Polyclonal antibodies are relatively easy to produce and may supplement monoclonal antibodies for some applications or even have some advantages. The choice of species for production of (peptide) antisera is based on practical considerations, including availability of immunogen (vaccine) and animals. Two major factors govern the production of antisera: the nature of adaptive immune responses, which take place over days/weeks and ethical guidelines for animal welfare. Here, simple procedures for immunization of mice, rabbits, sheep, goats, pigs, horses, and chickens are presented. PMID:26424267
Phytosulfokine peptide signalling.
Sauter, Margret
Phytosulfokine (PSK) belongs to the group of plant peptide growth factors. It is a disulfated pentapeptide encoded by precursor genes that are ubiquitously present in higher plants, suggestive of universal functions. Processing of the preproprotein involves sulfonylation by a tyrosylprotein sulfotransferase in the trans-golgi and proteolytic cleavage in the apoplast. The secreted peptide is perceived at the cell surface by a membrane-bound receptor kinase of the leucine-rich repeat family. The PSK receptor PSKR1 from Arabidopsis thaliana is an active kinase and has guanylate cyclase activity resulting in dual-signal outputs. Receptor activity is regulated by calmodulin. While PSK may be an autocrine growth factor, it also acts non-cell autonomously by promoting growth of cells that are receptor-deficient. In planta, PSK has multiple functions. It promotes cell growth, acts in the quiescent centre cells of the root apical meristem, contributes to funicular pollen tube guidance, and differentially alters immune responses depending on the pathogen. It has been suggested that PSK integrates growth and defence signals to balance the competing metabolic costs of these responses. This review summarizes our current understanding of PSK synthesis, signalling, and activity. PMID:25754406
Urinary Peptides in Rett Syndrome.
Solaas, K. M.; Skjeldal, O.; Gardner, M. L. G.; Kase, B. F.; Reichelt, K. L.
A study found a significantly higher level of peptides in the urine of 53 girls with Rett syndrome compared with controls. The elevation was similar to that in 35 girls with infantile autism. Levels of peptides were lower in girls with classic Rett syndrome than those with congenital Rett syndrome. (Contains references.) (Author/CR)
Peptide-LNA oligonucleotide conjugates
DEFF Research Database (Denmark)
Astakhova, I Kira; Hansen, Lykke Haastrup; Vester, Birte; Wengel, Jesper
Although peptide-oligonucleotide conjugates (POCs) are well-known for nucleic acids delivery and therapy, reports on internal attachment of peptides to oligonucleotides are limited in number. To develop a convenient route for preparation of internally labeled POCs with improved biomedical...
DEFF Research Database (Denmark)
Jensen, Knud Jørgen
This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....
Radiolabelled peptides for oncological diagnosis.
Laverman, P.; Sosabowski, J.K.; Boerman, O.C.; Oyen, W.J.G.
Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of resea
Conus venom peptide pharmacology.
Lewis, Richard J; Dutertre, Sébastien; Vetter, Irina; Christie, MacDonald J
Conopeptides are a diverse group of recently evolved venom peptides used for prey capture and/or defense. Each species of cone snails produces in excess of 1000 conopeptides, with those pharmacologically characterized (≈ 0.1%) targeting a diverse range of membrane proteins typically with high potency and specificity. The majority of conopeptides inhibit voltage- or ligand-gated ion channels, providing valuable research tools for the dissection of the role played by specific ion channels in excitable cells. It is noteworthy that many of these targets are found to be expressed in pain pathways, with several conopeptides having entered the clinic as potential treatments for pain [e.g., pyroglutamate1-MrIA (Xen2174)] and one now marketed for intrathecal treatment of severe pain [ziconotide (Prialt)]. This review discusses the diversity, pharmacology, structure-activity relationships, and therapeutic potential of cone snail venom peptide families acting at voltage-gated ion channels (ω-, μ-, μO-, δ-, ι-, and κ-conotoxins), ligand-gated ion channels (α-conotoxins, σ-conotoxin, ikot-ikot, and conantokins), G-protein-coupled receptors (ρ-conopeptides, conopressins, and contulakins), and neurotransmitter transporters (χ-conopeptides), with expanded discussion on the clinical potential of sodium and calcium channel inhibitors and α-conotoxins. Expanding the discovery of new bioactives using proteomic/transcriptomic approaches combined with high-throughput platforms and better defining conopeptide structure-activity relationships using relevant membrane protein crystal structures are expected to grow the already significant impact conopeptides have had as both research probes and leads to new therapies. PMID:22407615
Radiopharmaceutical development of radiolabelled peptides
Energy Technology Data Exchange (ETDEWEB)
Fani, Melpomeni; Maecke, Helmut R. [University Hospital Freiburg, Department of Nuclear Medicine, Freiburg (Germany)
Receptor targeting with radiolabelled peptides has become very important in nuclear medicine and oncology in the past few years. The overexpression of many peptide receptors in numerous cancers, compared to their relatively low density in physiological organs, represents the molecular basis for in vivo imaging and targeted radionuclide therapy with radiolabelled peptide-based probes. The prototypes are analogs of somatostatin which are routinely used in the clinic. More recent developments include somatostatin analogs with a broader receptor subtype profile or with antagonistic properties. Many other peptide families such as bombesin, cholecystokinin/gastrin, glucagon-like peptide-1 (GLP-1)/exendin, arginine-glycine-aspartic acid (RGD) etc. have been explored during the last few years and quite a number of potential radiolabelled probes have been derived from them. On the other hand, a variety of strategies and optimized protocols for efficient labelling of peptides with clinically relevant radionuclides such as {sup 99m}Tc, M{sup 3+} radiometals ({sup 111}In, {sup 86/90}Y, {sup 177}Lu, {sup 67/68}Ga), {sup 64/67}Cu, {sup 18}F or radioisotopes of iodine have been developed. The labelling approaches include direct labelling, the use of bifunctional chelators or prosthetic groups. The choice of the labelling approach is driven by the nature and the chemical properties of the radionuclide. Additionally, chemical strategies, including modification of the amino acid sequence and introduction of linkers/spacers with different characteristics, have been explored for the improvement of the overall performance of the radiopeptides, e.g. metabolic stability and pharmacokinetics. Herein, we discuss the development of peptides as radiopharmaceuticals starting from the choice of the labelling method and the conditions to the design and optimization of the peptide probe, as well as some recent developments, focusing on a selected list of peptide families, including somatostatin
Peptide primary messengers in plants
Institute of Scientific and Technical Information of China (English)
The peptide primary messengers regulate embryonic development,cell growth and many other activities in animal cells. But recent evidence verified that peptide primary messengers are also involved in plant defense responses, the recognition between pollen and stigma and keep the balance between cell proliferation and differentiations in shoot apical meristems. Those results suggest that plants may actually make wide use of peptide primary messengers, both in embryonic development and late life when they rally their cells to defend against pathogens and insect pests. The recent advance in those aspects is reviewed.
Screening of TACE Peptide Inhibitors from Phage Display Peptide Library
Institute of Scientific and Technical Information of China (English)
To obtain the recombinant tumor necrosis factor-α converting enzyme (TACE) ectodomain and use it as a selective molecule for the screening of TACE peptide inhibitors, the cDNA coding catalytic domain (T800) and full-length ectodomain (T1300) of TACE were amplified by RTPCR, and the expression plasmids were constructed by inserting T800 and T1300 into plasmid pET28a and pET-28c respectively. The recombinant T800 and T1300 were induced by IPTG, and SDSPAGE and Western blotting analysis results revealed that T800 and T1300 were highly expressed in the form of inclusion body. After Ni2+-NTA resin affinity chromatography, the recombinant proteins were used in the screening of TACE-binding peptides from phage display peptide library respectively. After 4 rounds of biopanning, the positive phage clones were analyzed by ELISA, competitive inhibition assay and DNA sequencing. A common amino acid sequence (TRWLVYFSRPYLVAT) was found and synthesized. The synthetic peptide could inhibit the TNF-α release from LPS-stimulated human peripheral blood mononuclear cells (PBMC) up to 60.3 %. FACS analysis revealed that the peptide mediated the accumulation of TNF-α on the cell surface. These results demonstrate that the TACE-binding peptide is an effective antagonist of TACE.
DEFF Research Database (Denmark)
Bundgaard, Louise; Jacobsen, Stine; Sorensen, Mette A.;
Progress in MS-based methods for veterinary research and diagnostics is lagging behind compared to the human research, and proteome data of domestic animals is still not well represented in open source data repositories. This is particularly true for the equine species. Here we present a first...... current release comprises 24 131 distinct peptides representing 2636 canonical proteins observed at false discovery rates of 0.2% at the peptide level and 1.4% at the protein level. Data from the Equine PeptideAtlas are available for experimental planning, validation of new datasets, and as a proteomic...... data mining resource. The advantages of the Equine PeptideAtlas are demonstrated by examples of mining the contents for information on potential and well-known equine acute phase proteins, which have extensive general interest in the veterinary clinic. The extracted information will support further...
Peptide nanostructures in biomedical technology.
Feyzizarnagh, Hamid; Yoon, Do-Young; Goltz, Mark; Kim, Dong-Shik
Nanostructures of peptides have been investigated for biomedical applications due to their unique mechanical and electrical properties in addition to their excellent biocompatibility. Peptides may form fibrils, spheres and tubes in nanoscale depending on the formation conditions. These peptide nanostructures can be used in electrical, medical, dental, and environmental applications. Applications of these nanostructures include, but are not limited to, electronic devices, biosensing, medical imaging and diagnosis, drug delivery, tissue engineering and stem cell research. This review offers a discussion of basic synthesis methods, properties and application of these nanomaterials. The review concludes with recommendations and future directions for peptide nanostructures. WIREs Nanomed Nanobiotechnol 2016, 8:730-743. doi: 10.1002/wnan.1393 For further resources related to this article, please visit the WIREs website. PMID:26846352
Production and characterization of peptide antibodies
DEFF Research Database (Denmark)
Trier, Nicole Hartwig; Hansen, Paul Robert; Houen, Gunnar
Proteins are effective immunogens for generation of antibodies. However, occasionally the native protein is known but not available for antibody production. In such cases synthetic peptides derived from the native protein are good alternatives for antibody production. These peptide antibodies are...... powerful tools in experimental biology and are easily produced to any peptide of choice. A widely used approach for production of peptide antibodies is to immunize animals with a synthetic peptide coupled to a carrier protein. Very important is the selection of the synthetic peptide, where factors such as......, including solid-phase peptide-carrier conjugation and peptide-carrier conjugation in solution. Upon immunization, adjuvants such as Al(OH)(3) are added together with the immunogenic peptide-carrier conjugate, which usually leads to high-titred antisera. Following immunization and peptide antibody...
Targeting cancer with peptide aptamers
Seigneuric, Renaud; Gobbo, Jessica; Colas, Pierre; Garrido, Carmen
A major endeavour in cancer chemotherapy is to develop agents that specifically target a biomolecule of interest. There are two main classes of targeting agents: small molecules and biologics. Among biologics (e.g.: antibodies), DNA, RNA but also peptide aptamers are relatively recent agents. Peptide aptamers are seldom described but represent attractive agents that can inhibit a growing panel of oncotargets including Heat Shock Proteins. Potential pitfalls and coming challenges towards succe...
Manufacturing of peptides exhibiting biological activity
Zambrowicz, Aleksandra; Timmer, Monika; Polanowski, Antoni; Lubec, Gert; Trziszka, Tadeusz
Numerous studies have shown that food proteins may be a source of bioactive peptides. Those peptides are encrypted in the protein sequence. They stay inactive within the parental protein until release by proteolytic enzymes (Mine and Kovacs-Nolan in Worlds Poult Sci J 62(1):87–95, 2006; Hartman and Miesel in Curr Opin Biotechnol 18:163–169, 2007). Once released the bioactive peptides exhibit several biofunctionalities and may serve therapeutic roles in body systems. Opioid peptides, peptides ...
Energy Technology Data Exchange (ETDEWEB)
Bachovchin, W.W.; Unkefer, C.J.
Advances in magnetic resonance and vibrational spectroscopy make it possible to derive detailed structural information about biomolecular structures in solution. These techniques are critically dependent on the availability of labeled compounds. For example, NMR techniques used today to derive peptide and protein structures require uniformity {sup 13}C-and {sup 15}N-labeled samples that are derived biosynthetically from (U-6-{sup 13}C) glucose. These experiments are possible now because, during the 1970s, the National Stable Isotope Resource developed algal methods for producing (U-6-{sup 13}C) glucose. If NMR techniques are to be used to study larger proteins, we will need sophisticated labelling patterns in amino acids that employ a combination of {sup 2}H, {sup 13}C, and {sup 15}N labeling. The availability of these specifically labeled amino acids requires a renewed investment in new methods for chemical synthesis of labeled amino acids. The development of new magnetic resonance or vibrational techniques to elucidate biomolecular structure will be seriously impeded if we do not see rapid progress in labeling technology. Investment in labeling chemistry is as important as investment in the development of advanced spectroscopic tools.
Antimicrobial peptides in annelids
Directory of Open Access Journals (Sweden)
A Tasiemski
Full Text Available Gene encoded antimicrobial peptides (AMPs are widely distributed among living organisms including plants, invertebrates and vertebrates. They constitute important effectors of the innate immune response by exerting multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis and immune induction. In invertebrates, most of the data describe the characterization and/or the function of AMPs in the numerically and economically most representative group which are arthropods. Annelids are among the first coelomates and are therefore of special phylogenetic interest. Compared to other invertebrate groups, data on annelid's immunity reveal heavier emphasis on the cellular than on the humoral response suggesting that immune defense of annelids seems to be principally developed as cellular immunity.This paper gives an overview of the variety of AMPs identified in the three classes of annelids, i.e. polychaetes, oligochaetes and achaetes. Their functions, when they have been studied, in the humoral or cellular response of annelids are also mentioned.
Regoli, Domenico; Gobeil, Fernand
This paper is divided into two sections: the first contains the essential elements of the opening lecture presented by Pr. Regoli to the 2015 International Kinin Symposium in S. Paulo, Brazil on June 28th and the second is the celebration of Dr. Regoli's 60 years of research on vasoactive peptides. The cardiovascular homeostasis derives from a balance of two systems, the renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS). The biologically active effector entity of RAS is angiotensin receptor-1 (AT-1R), and that of KKS is bradykinin B2 receptor (B2R). The first mediates vasoconstriction, the second is the most potent and efficient vasodilator. Thanks to its complex and multi-functional mechanism of action, involving nitric oxide (NO), prostacyclin and endothelial hyperpolarizing factor (EDHF). B2R is instrumental for the supply of blood, oxygen and nutrition to tissues. KKS is present on the vascular endothelium and functions as an autacoid playing major roles in cardiovascular diseases (CVDs) and diabetes. KKS exerts a paramount role in the prevention of thrombosis and atherosclerosis. Such knowledge emphasizes the already prominent value of the ACE-inhibitors (ACEIs) for the treatment of CVDs and diabetes. Indeed, the ACEIs, thanks to their double action (block of the RAS and potentiation of the KKS) are the ideal agents for a rational treatment of these diseases. PMID:26408609
Antimicrobial peptides in crustaceans
Directory of Open Access Journals (Sweden)
RD Rosa
Full Text Available Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP families are currently recognized, although the great majority (14 families comes from members of the order Decapoda. Crustacean AMPs are generally cationic, gene-encoded molecules that are mainly produced by circulating immune-competent cells (hemocytes or are derived from unrelated proteins primarily involved in other biological functions. In this review, we tentatively classified the crustacean AMPs into four main groups based on their amino acid composition, structural features and multi-functionality. We also attempted to summarize the current knowledge on their implication both in an efficient response to microbial infections and in crustacean survival.
Material Binding Peptides for Nanotechnology
Directory of Open Access Journals (Sweden)
Urartu Ozgur Safak Seker
Full Text Available Remarkable progress has been made to date in the discovery of material binding peptides and their utilization in nanotechnology, which has brought new challenges and opportunities. Nowadays phage display is a versatile tool, important for the selection of ligands for proteins and peptides. This combinatorial approach has also been adapted over the past decade to select material-specific peptides. Screening and selection of such phage displayed material binding peptides has attracted great interest, in particular because of their use in nanotechnology. Phage display selected peptides are either synthesized independently or expressed on phage coat protein. Selected phage particles are subsequently utilized in the synthesis of nanoparticles, in the assembly of nanostructures on inorganic surfaces, and oriented protein immobilization as fusion partners of proteins. In this paper, we present an overview on the research conducted on this area. In this review we not only focus on the selection process, but also on molecular binding characterization and utilization of peptides as molecular linkers, molecular assemblers and material synthesizers.
Collagen-like antimicrobial peptides.
Masuda, Ryo; Kudo, Masakazu; Dazai, Yui; Mima, Takehiko; Koide, Takaki
Combinatorial library composed of rigid rod-like peptides with a triple-helical scaffold was constructed. The component peptides were designed to have various combinations of basic and neutral (or hydrophobic) amino acid residues based on collagen-like (Gly-Pro-Yaa)-repeating sequences, inspired from the basic and amphiphilic nature of naturally occurring antimicrobial peptides. Screening of the peptide pools resulted in identification of antimicrobial peptides. A structure-activity relationship study revealed that the position of Arg-cluster at N-terminus and cystine knots at C-terminus in the triple helix significantly contributed to the antimicrobial activity. The most potent peptide RO-A showed activity against Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. In addition, Escherichia coli exposed to RO-A resulted in abnormal elongation of the cells. RO-A was also shown to have remarkable stability in human serum and low cytotoxicity to mammalian cells. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 453-459, 2016. PMID:27271210
Automated solid-phase peptide synthesis to obtain therapeutic peptides
Directory of Open Access Journals (Sweden)
Veronika Mäde
Full Text Available The great versatility and the inherent high affinities of peptides for their respective targets have led to tremendous progress for therapeutic applications in the last years. In order to increase the drugability of these frequently unstable and rapidly cleared molecules, chemical modifications are of great interest. Automated solid-phase peptide synthesis (SPPS offers a suitable technology to produce chemically engineered peptides. This review concentrates on the application of SPPS by Fmoc/t-Bu protecting-group strategy, which is most commonly used. Critical issues and suggestions for the synthesis are covered. The development of automated methods from conventional to essentially improved microwave-assisted instruments is discussed. In order to improve pharmacokinetic properties of peptides, lipidation and PEGylation are described as covalent conjugation methods, which can be applied by a combination of automated and manual synthesis approaches. The synthesis and application of SPPS is described for neuropeptide Y receptor analogs as an example for bioactive hormones. The applied strategies represent innovative and potent methods for the development of novel peptide drug candidates that can be manufactured with optimized automated synthesis technologies.
Perspectives and Peptides of the Next Generation
Brogden, Kim A.
Shortly after their discovery, antimicrobial peptides from prokaryotes and eukaryotes were recognized as the next potential generation of pharmaceuticals to treat antibiotic-resistant bacterial infections and septic shock, to preserve food, or to sanitize surfaces. Initial research focused on identifying the spectrum of antimicrobial agents, determining the range of antimicrobial activities against bacterial, fungal, and viral pathogens, and assessing the antimicrobial activity of synthetic peptides versus their natural counterparts. Subsequent research then focused on the mechanisms of antimicrobial peptide activity in model membrane systems not only to identify the mechanisms of antimicrobial peptide activity in microorganisms but also to discern differences in cytotoxicity for prokaryotic and eukaryotic cells. Recent, contemporary work now focuses on current and future efforts to construct hybrid peptides, peptide congeners, stabilized peptides, peptide conjugates, and immobilized peptides for unique and specific applications to control the growth of microorganisms in vitro and in vivo.
Exploration of the Medicinal Peptide Space.
Gevaert, Bert; Stalmans, Sofie; Wynendaele, Evelien; Taevernier, Lien; Bracke, Nathalie; D'Hondt, Matthias; De Spiegeleer, Bart
The chemical properties of peptide medicines, known as the 'medicinal peptide space' is considered a multi-dimensional subset of the global peptide space, where each dimension represents a chemical descriptor. These descriptors can be linked to biofunctional, medicinal properties to varying degrees. Knowledge of this space can increase the efficiency of the peptide-drug discovery and development process, as well as advance our understanding and classification of peptide medicines. For 245 peptide drugs, already available on the market or in clinical development, multivariate dataexploration was performed using peptide relevant physicochemical descriptors, their specific peptidedrug target and their clinical use. Our retrospective analysis indicates that clusters in the medicinal peptide space are located in a relatively narrow range of the physicochemical space: dense and empty regions were found, which can be explored for the discovery of novel peptide drugs. PMID:26876881
Peptide-enhanced oral delivery of therapeutic peptides and proteins
DEFF Research Database (Denmark)
Kristensen, Mie; Foged, Camilla; Berthelsen, Jens;
such as the cell penetrating peptides (CPPs) and the tight junction modulating peptides (TJMPs), which are able to translocate across the cellular membranes in a non-disruptive way or reversibly modulate the integrity of intercellular tight junctions (TJs), respectively. However, because of the harsh...... believed that CPP-mediated translocation involves transcytosis and/or direct translocation through the epithelial cells; whereas TJMP-mediated translocation is dependent on interaction with transmembrane or peripheral TJ proteins. This review focuses on the CPPs and the TJMPs currently employed as...
Double-Stranded Peptide Nucleic Acids
DEFF Research Database (Denmark)
A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker.......A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....
Recent development of peptide self-assembly
Institute of Scientific and Technical Information of China (English)
Xiubo Zhao; Fang Pan; Jian R. Lu
Amino acids are the building blocks to build peptides and proteins. Recent development in peptide synthesis has however enabled us to mimic this natural process by preparing various long and short peptides possessing different conformations and biological functions. The self-assembly of short designed peptides into molecular nanostructures is becoming a growing interest in nanobiotechnology. Self-assembled peptides exhibit several attractive features for applications in tissue regeneration, drug delivery, biological surface engineering as well as in food science, cosmetic industry and antibiotics. The aim of this review is to introduce the readers to a number of representative studies on peptide self-assembly.
Antiviral active peptide from oyster
Zeng, Mingyong; Cui, Wenxuan; Zhao, Yuanhui; Liu, Zunying; Dong, Shiyuan; Guo, Yao
An active peptide against herpes virus was isolated from the enzymic hydrolysate of oyster ( Crassostrea gigas) and purified with the definite direction hydrolysis technique in the order of alcalase and bromelin. The hydrolysate was fractioned into four ranges of molecular weight (>10 kDa, 10 5 kDa, 5 1 kDa and <1 kDa) using ultrafiltration membranes and dialysis. The fraction of 10 5 kDa was purified using consecutive chromatographic methods including DEAE Sephadex A-25 column, Sephadex G-25 column, and high performance liquid chromatogram (HPLC) by activity-guided isolation. The antiviral effect of the obtained peptide on herpetic virus was investigated in Vero cells by observing cytopathic effect (CPE). The result shows that the peptide has high inhibitory activity on herpetic virus.
Radioactive labelling of peptidic hormones
International Nuclear Information System (INIS)
The labelling of peptidic hormones requires stability, specificity and sensitivity of the label. Introduction of a radioactive atome is one way to satisfy these criteria. Several processes have been described to prepare radioactive TRF: synthesis of the peptide with labelled aminoacids or introduction of the label into the hormone. In that approach, tritium can be substituted in the imidazole ring, via precursors activating the proper carbon. Monoiodo TRF leads essentially to tritium labelling of the 5 positions whereas monoazo TRF allows the preparation of 3H TRF labelled in the 2 positions. Di-substituted TRF leads to labelling into the 2 and 5 carbons. Labelled analogs of TRF can be prepared with labelled iodine; further developments of peptide labelling, will be presented. In particular, the homolytic scission of the C-iodine, bond by photochemical activation. The nascent carbon radical can be stabilized by a tritiated scavenger. This approach eliminates the use of heavy metal catalysts
Antiviral active peptide from oyster
Institute of Scientific and Technical Information of China (English)
An active peptide against herpes virus was isolated from the enzymic hydrolysate of oyster (Crassostrea gigas) and purified with the definite direction hydrolysis technique in the order of alcalase and bromelin. The hydrolysate was fractioned into four ranges of molecular weight (>10 kDa, 10-5 kDa, 5-1 kDa and <1 kDa) using ultrafiltration membranes and dialysis. The fraction of 10?5 kDa was purified using consecutive chromatographic methods including DEAE Sephadex A-25 column, Sephadex G-25 column, and high performance liquid chromatogram (HPLC) by activity-guided isolation. The antiviral effect of the obtained peptide on herpetic virus was investigated in Vero cells by observing cytopathic effect (CPE). The result shows that the peptide has high inhibitory activity on herpetic virus.
Peptide Antibiotics for ESKAPE Pathogens
DEFF Research Database (Denmark)
Thomsen, Thomas Thyge
developed from a cecropin-mellitin hybrid peptide and proved effective in killing colistin resistant Gram-negative A. baumannii in vitro. The molecule was improved with regard to toxicity, as measured by hemolytic ability. Further, this peptide is capable of specifically killing non-growing cells of...... colistin resistant A. baumannii, also known as persisters. Using D. melanogaster as an in vivo efficacy model it was demonstrated that the Lantibiotic NAI- 107, currently undergoing pre-clinical studies, rescues D. melanogaster from MRSA infection with similar efficacy to last resort antimicrobial...
Novel Formulations for Antimicrobial Peptides
Directory of Open Access Journals (Sweden)
Ana Maria Carmona-Ribeiro
Full Text Available Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.
Peptides and the new endocrinology
Schwyzer, Robert
The discovery of regulatory peptides common to the nervous and the endocrine systems (brain, gut, and skin) has brought about a revolution in our concepts of endocrinology and neurology. We are beginning to understand some of the complex interrelationships between soma and psyche that might, someday, be important for an integrated treatment of diseases. Examples of the actions of certain peptides in the periphery and in the central nervous system are given, and their biosynthesis and molecular anatomy as carriers for information are discussed.
Natriuretic peptides and cerebral hemodynamics
DEFF Research Database (Denmark)
Guo, Song; Barringer, Filippa; Zois, Nora Elisabeth;
decompensated disease. In contrast, their biological effects on the cerebral hemodynamics are poorly understood. In this mini-review, we summarize the hemodynamic effects of the natriuretic peptides with a focus on the cerebral hemodynamics. In addition, we will discuss its potential implications in diseases...... where alteration of the cerebral hemodynamics plays a role such as migraine and acute brain injury including stroke. We conclude that a possible role of the peptides is feasible as evaluated from animal and in vitro studies, but more research is needed in humans to determine the precise response on...... cerebral vessels....
Neuroprotective peptides related to Alzheimer's disease
Czech Academy of Sciences Publication Activity Database
Slaninová, Jiřina; Borovičková, Lenka; Krejčová, G.; Patočka, J.
Roč. 10, S (2004), s. H33. ISSN 1075-2617. [Hellenic Forum on Bioactive Peptides /4./. 22.04.2004-24.04.2004, Patras-Hellas] Keywords : neuroprotective peptides * Alzheimer's disease Subject RIV: CE - Biochemistry
Histidine-Containing Peptide Nucleic Acids
DEFF Research Database (Denmark)
Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics.......Peptide nucleic acids containing histidine moieties are provided. These compounds have applications including diagnostics, research and potential therapeutics....
Lipoxygenase inhibitor peptides and their use
Schurink, M.; Boeriu, C.G.; Berkel, van, A.M.; Wichers, H.J.
The present invention is in the field of enzyme inhibition. In particular it relates to peptide inhibitors for lipoxygenases. The lipoxygenase peptide inhibitors of have the potential to be used as therapeutic drugs as well as food preservatives.
Strategic approaches to optimizing peptide ADME properties.
Di, Li
Development of peptide drugs is challenging but also quite rewarding. Five blockbuster peptide drugs are currently on the market, and six new peptides received first marketing approval as new molecular entities in 2012. Although peptides only represent 2% of the drug market, the market is growing twice as quickly and might soon occupy a larger niche. Natural peptides typically have poor absorption, distribution, metabolism, and excretion (ADME) properties with rapid clearance, short half-life, low permeability, and sometimes low solubility. Strategies have been developed to improve peptide drugability through enhancing permeability, reducing proteolysis and renal clearance, and prolonging half-life. In vivo, in vitro, and in silico tools are available to evaluate ADME properties of peptides, and structural modification strategies are in place to improve peptide developability. PMID:25366889
Purification, structure and function of bioactive peptides
Eriste, Elo
Peptides are vitally important molecules and many evoke cellular responses. The completion of several genome sequencing projects has revealed a number of new genes. However, as functional peptides often contain posttranslational modifications and/or occur at various lengths, it is of great importance to detect, purify and characterize novel bioactive peptides. To achieve these goals, new methods for peptide detection, isolation and functional characterization have to be d...
Natriuretic Peptide Metabolism, Clearance and Degradation
Potter, Lincoln R.
Atrial natriuretic peptide, B-type natriuretic peptide and C-type natriuretic peptide compose a family of three structurally related, but genetically distinct, signaling molecules that regulate the cardiovascular, skeletal, nervous, reproductive and other systems by activating transmembrane guanylyl cyclases and elevating intracellular cGMP concentrations. This review broadly discusses the general characteristics of natriuretic peptides and their cognate signaling receptors, then specifically...
Milk proteins as precursors of bioactive peptides
Marta Dziuba; Bartłomiej Dziuba; Anna Iwaniak
Milk proteins, a source of bioactive peptides, are the subject of numerous research studies aiming to, among others, evaluate their properties as precursors of biologically active peptides. Physiologically active peptides released from their precursors may interact with selected receptors and affect the overall condition and health of humans. By relying on the BIOPEP database of proteins and bioactive peptides, developed by the Department of Food Biochemistry at the University of Warmia and M...
Diversity of wheat anti-microbial peptides.
Egorov, Tsezi A; Odintsova, Tatyana I; Pukhalsky, Vitaliy A; Grishin, Eugene V
From seeds of Triticum kiharae Dorof. et Migusch., 24 novel anti-microbial peptides were isolated and characterized by a combination of three-step HPLC (affinity, size-exclusion and reversed-phase) with matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and Edman degradation. Based on sequence similarity and cysteine motifs, partially sequenced peptides were assigned to 7 families: defensins, thionins, lipid-transfer proteins, hevein-like peptides, knottin-like peptides, glycine-rich peptides, and MBP-1 homologs. A novel subfamily of defensins consisting of 6 peptides and a new family of glycine-rich (8 peptides with different repeat motifs) were identified. Three 6-cysteine knottin-like peptides represented by N- and C-terminally truncated variants revealed no sequence homology to any known plant anti-microbial peptides. A new 8-cysteine hevein-like peptide and three 4-cysteine peptides homologous to MBP-1 from maize were isolated. This is the first communication on the occurrence of nearly all families of plant anti-microbial peptides in a single species. PMID:16269343
Characterization of Synthetic Peptides by Mass Spectrometry
DEFF Research Database (Denmark)
Prabhala, Bala K; Mirza, Osman; Højrup, Peter;
Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI-TOF-MS and...
Unsupervised Identification of Isotope-Labeled Peptides.
Goldford, Joshua E; Libourel, Igor G L
In vivo isotopic labeling coupled with high-resolution proteomics is used to investigate primary metabolism in techniques such as stable isotope probing (protein-SIP) and peptide-based metabolic flux analysis (PMFA). Isotopic enrichment of carbon substrates and intracellular metabolism determine the distribution of isotopes within amino acids. The resulting amino acid mass distributions (AMDs) are convoluted into peptide mass distributions (PMDs) during protein synthesis. With no a priori knowledge on metabolic fluxes, the PMDs are therefore unknown. This complicates labeled peptide identification because prior knowledge on PMDs is used in all available peptide identification software. An automated framework for the identification and quantification of PMDs for nonuniformly labeled samples is therefore lacking. To unlock the potential of peptide labeling experiments for high-throughput flux analysis and other complex labeling experiments, an unsupervised peptide identification and quantification method was developed that uses discrete deconvolution of mass distributions of identified peptides to inform on the mass distributions of otherwise unidentifiable peptides. Uniformly (13)C-labeled Escherichia coli protein was used to test the developed feature reconstruction and deconvolution algorithms. The peptide identification was validated by comparing MS(2)-identified peptides to peptides identified from PMDs using unlabeled E. coli protein. Nonuniformly labeled Glycine max protein was used to demonstrate the technology on a representative sample suitable for flux analysis. Overall, automatic peptide identification and quantification were comparable or superior to manual extraction, enabling proteomics-based technology for high-throughput flux analysis studies. PMID:27145348
Bioactive peptides in dairy products
Directory of Open Access Journals (Sweden)
Donata Marletta
Full Text Available Bioactive peptides are specific protein fragments that have a positive impact on body functions and conditions and may ultimately influence health. Most of the biological activities are encrypted within the primary sequence of the native protein and can be released by enzymatic hydrolysis and proteolysis or by food processing. Milk is a rich source of bioactive peptides which may contribute to regulate the nervous, gastrointestinal and cardiovascular systems as well as the immune system, confirming the added value of dairy products that, in certain cases, can be considered functional foods. The main biological activities of these peptides and their bioavailability in dairy products are reviewed. The natural concentration of these biomolecules is quite low and, to date one of the main goals has been to realize products enriched with bioactive peptides that have beneficial effects on human health and proven safety. Even though several health-enhancing products have already been launched and their integration in the diet could help in the prevention of chronic diseases such as hypertension, cancer and osteoporosis, more clinical trials are required in order to develop a deeper understanding of the activity of biopeptides on the human physiological mechanisms and also to assess the efficacy of their effects in a long term view. New scientific data are also needed to support their commercialisation in compliance with current regulations.
Study of antimicrobial peptides by capillary electrophoresis
Czech Academy of Sciences Publication Activity Database
Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav
Sofia: Bulgarian Peptide Society, 2015 - (Naydenova, E.; Pajpanova, T.; Danalev, D.), s. 304-305 ISBN 978-619-90427-2-4. [Peptides 2014. European Peptide Symposium /33./. Sofia (BG), 31.08.2014-05.09.2014] R&D Projects: GA ČR(CZ) GAP206/12/0453; GA ČR(CZ) GA13-17224S Institutional support: RVO:61388963 Keywords : peptides * antimicrobial activity * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation http://bulpepsoc.info/wp-content/uploads/2015/06/PEPTIDES-2014-electronic-version.pdf
Natural and synthetic peptides with antifungal activity.
Ciociola, Tecla; Giovati, Laura; Conti, Stefania; Magliani, Walter; Santinoli, Claudia; Polonelli, Luciano
In recent years, the increase of invasive fungal infections and the emergence of antifungal resistance stressed the need for new antifungal drugs. Peptides have shown to be good candidates for the development of alternative antimicrobial agents through high-throughput screening, and subsequent optimization according to a rational approach. This review presents a brief overview on antifungal natural peptides of different sources (animals, plants, micro-organisms), peptide fragments derived by proteolytic cleavage of precursor physiological proteins (cryptides), synthetic unnatural peptides and peptide derivatives. Antifungal peptides are schematically reported based on their structure, antifungal spectrum and reported effects. Natural or synthetic peptides and their modified derivatives may represent the basis for new compounds active against fungal infections. PMID:27502155
Encapsulation of bioactive whey peptides in soy lecithin-derived nanoliposomes: Influence of peptide molecular weight.
Mohan, Aishwarya; McClements, David Julian; Udenigwe, Chibuike C
Encapsulation of peptides can be used to enhance their stability, delivery and bioavailability. This study focused on the effect of the molecular weight range of whey peptides on their encapsulation within soy lecithin-derived nanoliposomes. Peptide molecular weight did not have a major impact on encapsulation efficiency or liposome size. However, it influenced peptide distribution amongst the surface, core, and bilayer regions of the liposomes, as determined by electrical charge (ζ-potential) and FTIR analysis. The liposome ζ-potential depended on peptide molecular weight, suggesting that the peptide charged groups were in different locations relative to the liposome surfaces. FTIR analysis indicated that the least hydrophobic peptide fractions interacted more strongly with choline on the liposome surfaces. The results suggested that the peptides were unequally distributed within the liposomes, even at the same encapsulation efficiency. These findings are important for designing delivery systems for commercial production of encapsulated peptides with improved functional attributes. PMID:27451165
New vasoactive peptides in cirrhosis
DEFF Research Database (Denmark)
Kimer, Nina; Goetze, Jens Peter; Bendtsen, Flemming;
to haemodynamic changes in the pro-peptides copeptin, proadrenomedullin and pro-atrial natriuretic peptide (proANP) in patients with cirrhosis. MATERIALS AND METHODS: Fifty-four cirrhotic patients and 15 controls were characterized haemodynamically during a liver vein catheterization. Copeptin......, proadrenomedullin and proANP were measured in hepatic and renal veins and the femoral artery. RESULTS: We found no differences in concentrations of copeptin and proadrenomedullin between patients and controls. ProANPs were higher in cirrhotic patients, median 138 pm (25/75 percentiles 101-194) compared with....... We found no extraction of copeptin, proadrenomedullin or proANP over the liver. Copeptin correlated with portal pressure (R=0·50, P<0·001). Proadrenomedullin correlated with portal pressure (R=0·48, P<0·001) and heart rate (R=0·36, P<0·01). ProANP correlated with cardiac output (R=0·46, P<0·002) and...
Structural transition in peptide nanotubes.
Amdursky, Nadav; Beker, Peter; Koren, Itai; Bank-Srour, Becky; Mishina, Elena; Semin, Sergey; Rasing, Theo; Rosenberg, Yuri; Barkay, Zahava; Gazit, Ehud; Rosenman, Gil
Phase transitions in organic and inorganic materials are well-studied classical phenomena, where a change in the crystal space group symmetry induces a wide variation of physical properties, permitted by the crystalline symmetry in each phase. Here we observe a conformational induced transition in bioinspired peptide nanotubes (PNTs). We found that the PNTs change their original molecular assembly from a linear peptide conformation to a cyclic one, followed by a change of the nanocrystalline structure from a noncentrosymmetric hexagonal space group to a centrosymmetric orthorhombic space group. The observed transition is irreversible and induces a profound variation in the PNTs properties, from the microscopic to the macroscopic level. In this context, we follow the unique changes in the molecular, morphological, piezoelectric, second harmonic generation, and wettability properties of the PNTs. PMID:21388228
Lifescience Database Archive (English)
Full Text Available FIELD NO 600781 FIELD TI 600781 PEPTIDE YY; PYY FIELD TX CLONING PYY is secreted from endocrine ... acologically active PYY(3-36)) were measured in 66 lean , 18 anorectic, 63 obese, and 16 morbidly obese hum ... +/- 12.9 pg/ml, P = less than 0.05) compared with lean ... (52.4 +/- 4.6 pg/ml), obese (43.9 +/- 3.8 pg/ml), ...
Antibody Peptide Based Antifungal Immunotherapy
Magliani, Walter; Conti, Stefania; Giovati, Laura; Zanello, Pier Paolo; Sperindè, Martina; Ciociola, Tecla; Polonelli, Luciano
Fungal infections still represent relevant human illnesses worldwide and some are accompanied by unacceptably high mortality rates. The limited current availability of effective and safe antifungal agents makes the development of new drugs and approaches of antifungal vaccination/immunotherapy every day more needed. Among them, small antibody(Ab)-derived peptides are arousing great expectations as new potential antifungal agents. In this topic, the search path from the study of the yeast kill...
Antimicrobial Peptides: Versatile Biological Properties
Directory of Open Access Journals (Sweden)
Muthuirulan Pushpanathan
Full Text Available Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries.
Antihypertensive Peptides from Milk Proteins
Directory of Open Access Journals (Sweden)
Heikki Vapaatalo
Full Text Available Dietary proteins possess a wide range of nutritional and functional properties. They are used as a source of energy and amino acids, which are needed for growth and development. Many dietary proteins, especially milk proteins, contain physiologically active peptides encrypted in the protein sequence. These peptides may be released during gastrointestinal digestion or food processing and once liberated, cause different physiological functions. Milk-derived bioactive peptides are shown to have antihypertensive, antimicrobial, immunomodulatory, antioxidative and mineral-binding properties. During the fermentation of milk with certain lactobacilli, two interesting tripeptides Ile-Pro-Pro and Val-Pro-Pro are released from casein to the final product. These lactotripeptides have attenuated the development of hypertension in several animal models and lowered blood pressure in clinical studies. They inhibit ACE in vitro at micromolar concentrations, protect endothelial function in vitro and reduce arterial stiffness in humans. Thus, milk as a traditional food product can after certain processing serve as a functional food and carry specific health-promoting effects, providing an option to control blood pressure.
Identification of novel human immunodeficiency virus type 1-inhibitory peptides based on the antimicrobial peptide database.
Wang, Guangshun; Watson, Karen M; Peterkofsky, Alan; Buckheit, Robert W
To identify novel anti-HIV-1 peptides based on the antimicrobial peptide database (APD; http://aps.unmc.edu/AP/main.php), we have screened 30 candidates and found 11 peptides with 50% effective concentrations (EC(50)) of 1, increases in the Arg contents of amphibian maximin H5 and dermaseptin S9 peptides and the database-derived GLK-19 peptide improved the TIs. These examples demonstrate that the APD is a rich resource and a useful tool for developing novel HIV-1-inhibitory peptides. PMID:20086159
Toxins and antimicrobial peptides: interactions with membranes
Schlamadinger, Diana E.; Gable, Jonathan E.; Kim, Judy E.
The innate immunity to pathogenic invasion of organisms in the plant and animal kingdoms relies upon cationic antimicrobial peptides (AMPs) as the first line of defense. In addition to these natural peptide antibiotics, similar cationic peptides, such as the bee venom toxin melittin, act as nonspecific toxins. Molecular details of AMP and peptide toxin action are not known, but the universal function of these peptides to disrupt cell membranes of pathogenic bacteria (AMPs) or a diverse set of eukaryotes and prokaryotes (melittin) is widely accepted. Here, we have utilized spectroscopic techniques to elucidate peptide-membrane interactions of alpha-helical human and mouse AMPs of the cathelicidin family as well as the peptide toxin melittin. The activity of these natural peptides and their engineered analogs was studied on eukaryotic and prokaryotic membrane mimics consisting of melittin and human cathelicidin embedded in bilayer vesicles. Collectively, our results provide clues to the functional structures of the engineered and toxic peptides and may impact the design of synthetic antibiotic peptides that can be used against the growing number of antibiotic-resistant pathogens.
Chemical Methods for Peptide and Protein Production
Directory of Open Access Journals (Sweden)
Istvan Toth
Full Text Available Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported a-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.
Predicting protein-peptide interactions from scratch
Yan, Chengfei; Xu, Xianjin; Zou, Xiaoqin; Zou lab Team
Protein-peptide interactions play an important role in many cellular processes. The ability to predict protein-peptide complex structures is valuable for mechanistic investigation and therapeutic development. Due to the high flexibility of peptides and lack of templates for homologous modeling, predicting protein-peptide complex structures is extremely challenging. Recently, we have developed a novel docking framework for protein-peptide structure prediction. Specifically, given the sequence of a peptide and a 3D structure of the protein, initial conformations of the peptide are built through protein threading. Then, the peptide is globally and flexibly docked onto the protein using a novel iterative approach. Finally, the sampled modes are scored and ranked by a statistical potential-based energy scoring function that was derived for protein-peptide interactions from statistical mechanics principles. Our docking methodology has been tested on the Peptidb database and compared with other protein-peptide docking methods. Systematic analysis shows significantly improved results compared to the performances of the existing methods. Our method is computationally efficient and suitable for large-scale applications. Nsf CAREER Award 0953839 (XZ) NIH R01GM109980 (XZ).
Construction of Lasso Peptide Fusion Proteins.
Zong, Chuhan; Maksimov, Mikhail O; Link, A James
Lasso peptides are a family of ribosomally synthesized and post-translationally modified peptides (RiPPs) typified by an isopeptide-bonded macrocycle between the peptide N-terminus and an aspartate or glutamate side chain. The C-terminal portion of the peptide threads through the N-terminal macrocycle to give the characteristic lasso fold. Because of the inherent stability, both proteolytic and often thermal, of lasso peptides, we became interested in whether proteins could be fused to the free C-terminus of lasso peptides. Here, we demonstrate fusion of two model proteins, the artificial leucine zipper A1 and the superfolder variant of GFP, to the C-terminus of the lasso peptide astexin-1. Successful lasso cyclization of the N-terminus of these fusion proteins requires a flexible linker in between the C-terminus of the lasso peptide and the N-terminus of the protein of interest. The ability to fuse lasso peptides to a protein of interest is an important step toward phage and bacterial display systems for the high-throughput screening of lasso peptide libraries for new functions. PMID:26492187
Human Antimicrobial Peptides and Proteins
Directory of Open Access Journals (Sweden)
Guangshun Wang
Full Text Available As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32 can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized
Synthesis of peptide .alpha.-thioesters
Camarero, Julio A.; Mitchell, Alexander R.; De Yoreo, James J.
Disclosed herein is a new method for the solid phase peptide synthesis (SPPS) of C-terminal peptide .alpha. thioesters using Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazine linker, which is totally stable to conditions required for Fmoc-SPPS. When the peptide synthesis has been completed, activation of the linker is achieved by mild oxidation. The oxidation step converts the acyl-hydrazine group into a highly reactive acyl-diazene intermediate which reacts with an .alpha.-amino acid alkylthioester (H-AA-SR) to yield the corresponding peptide .alpha.-thioester in good yield. A variety of peptide thioesters, cyclic peptides and a fully functional Src homology 3 (SH3) protein domain have been successfully prepared.
Prediction of twin-arginine signal peptides
DEFF Research Database (Denmark)
Bendtsen, Jannick Dyrløv; Nielsen, Henrik; Widdick, D.; Palmer, T.; Brunak, Søren
publicly available method, TatP, for prediction of bacterial Tat signal peptides. Results: We have retrieved sequence data for Tat substrates in order to train a computational method for discrimination of Sec and Tat signal peptides. The TatP method is able to positively classify 91% of 35 known Tat signal...... complementary rule based prediction method. Conclusion: The method developed here is able to discriminate Tat signal peptides from cytoplasmic proteins carrying a similar motif, as well as from Sec signal peptides, with high accuracy. The method allows filtering of input sequences based on Perl syntax regular...... expressions, whereas hydrophobicity discrimination of Tat- and Sec- signal peptides is carried out by an artificial neural network. A potential cleavage site of the predicted Tat signal peptide is also reported. The TatP prediction server is available as a public web server at http://www.cbs.dtu.dk/services/TatP/....
Use of Galerina marginata genes and proteins for peptide production
Energy Technology Data Exchange (ETDEWEB)
Hallen-Adams, Heather E.; Scott-Craig, John S.; Walton, Jonathan D.; Luo, Hong
The present invention relates to compositions and methods comprising genes and peptides associated with cyclic peptides and cyclic peptide production in mushrooms. In particular, the present invention relates to using genes and proteins from Galerina species encoding peptides specifically relating to amatoxins in addition to proteins involved with processing cyclic peptide toxins. In a preferred embodiment, the present invention also relates to methods for making small peptides and small cyclic peptides including peptides similar to amanitin. Further, the present inventions relate to providing kits for making small peptides.
Highly selective enrichment of phosphorylated peptides from peptide mixtures using titanium dioxide microcolumns
DEFF Research Database (Denmark)
Larsen, Martin Røssel; Thingholm, Tine E; Jensen, Ole N;
not. Other substituted aromatic carboxylic acids were also capable of specifically reducing binding of nonphosphorylated peptides, whereas phosphoric acid reduced binding of both phosphorylated and nonphosphorylated peptides. A putative mechanism for this intriguing effect is presented....
Antimicrobial Peptides in Toroidal and Cylindrical Pores
Mihajlovic, Maja; Lazaridis, Themis
Antimicrobial peptides (AMPs) are small, usually cationic peptides, which permeabilize biological membranes. Their mechanism of action is still not well understood. Here we investigate the preference of alamethicin and melittin for pores of different shapes, using molecular dynamics (MD) simulations of the peptides in pre-formed toroidal and cylindrical pores. When an alamethicin hexamer is initially embedded in a cylindrical pore, at the end of the simulation the pore remains cylindrical or ...
Interaction of small peptides with lipid bilayers.
Damodaran, K. V.; Merz, K M; Gaber, B P
Molecular dynamics simulations of the tripeptide Ala-Phe-Ala-O-tert-butyl interacting with dimyristoylphosphatidylcholine lipid bilayers have been carried out. The lipid and aqueous environments of the peptide, the alkyl chain order, and the lipid and peptide dynamics have been investigated with use of density profiles, radial distribution functions, alkyl chain order parameter profiles, and time correlation functions. It appears that the alkyl chain region accommodates the peptides in the bi...
Self-assembly of tetraphenylalanine peptides
Mayans Tayadella, Enric; Ballano Ballano, María Gema; Casanovas Salas, Jordi; Díaz Andrade, Angélica María; Pérez Madrigal, Maria del Mar; Estrany Coda, Francesc; Puiggalí Bellalta, Jordi; Cativiela Marín, Carlos A.; Alemán Llansó, Carlos
Three different tetraphenylalanine (FFFF) based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies under a variety of conditions. The FFFF peptide assembles into nanotubes that show more structural imperfections at the surface than those formed by the diphenylalanine (FF) peptide under the same conditions. Periodic DFT calculations (M06L functional) were used to propose a model that consists o...
Salt-resistant short antimicrobial peptides.
Mohanram, Harini; Bhattacharjya, Surajit
Antimicrobial peptides (AMPs) are promising leads for the development of antibiotics against drug resistant bacterial pathogens. However, in vivo applications of AMPs remain obscure due to salt and serum mediated inactivation. The high cost of chemical synthesis of AMPs also impedes potential clinical application. Consequently, short AMPs resistant toward salt and serum inactivation are desirable for the development of peptide antibiotics. In this work, we designed a 12-residue amphipathic helical peptide RR12 (R-R-L-I-R-L-I-L-R-L-L-R-amide) and two Trp containing analogs of RR12 namely RR12Wpolar (R-R-L-I-W-L-I-L-R-L-L-R-amide), and RR12Whydro (R-R-L-I-R-L-W-L-R-L-L-R-amide). Designed peptides demonstrated potent antibacterial activity; MIC ranging from 2 to 8 μM, in the presence of sodium chloride (150 mM and 300 mM). Antibacterial activity of these peptides was also detected in the presence of human serum. Designed peptides, in particular RR12 and RR12Whydro, were only poorly hemolytic. As a mode of action; these peptides demonstrated efficient permeabilization of bacterial cell membrane and lysis of cell structure. We further investigated interactions of the designed peptides with lipopolysaccharide (LPS), the major component of the outer membrane permeability barrier of Gram-negative bacteria. Designed peptides adopted helical conformations in complex with LPS. Binding of peptides with LPS has yielded dissociation the aggregated structures of LPS. Collectively, these designed peptides hold ability to be developed for salt-resistant antimicrobial compounds. Most importantly, current work provides insights for designing salt-resistant antimicrobial peptides. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 345-356, 2016. PMID:26849911
Pulmonary clearance of vasoactive intestinal peptide.
Barrowcliffe, M P; Morice, A; Jones, J G; Sever, P S
Vasoactive intestinal peptide causes bronchodilatation when given intravenously but is less effective in both animals and man when given by inhalation. This difference may be due to poor transit of the peptide across the bronchial epithelium. To test this hypothesis pulmonary clearance of radiolabelled vasoactive intestinal peptide was measured in Sprague Dawley rats and compared with that of pertechnetate (TcO4-) and diethylene triamine pentaacetate (DTPA). Despite a molecular weight (MW) of...
Genome-based peptide fingerprint scanning
Giddings, Michael C.; Shah, Atul A.; Gesteland, Ray; Moore, Barry
We have implemented a method that identifies the genomic origins of sample proteins by scanning their peptide-mass fingerprint against the theoretical translation and proteolytic digest of an entire genome. Unlike previously reported techniques, this method requires no predefined ORF or protein annotations. Fixed-size windows along the genome sequence are scored by an equation accounting for the number of matching peptides, the number of missed enzymatic cleavages in each peptide, the number ...
Membrane Perturbation Induced by Interfacially Adsorbed Peptides
Zemel, Assaf; Ben-Shaul, Avinoam; May, Sylvio
The structural and energetic characteristics of the interaction between interfacially adsorbed (partially inserted) α-helical, amphipathic peptides and the lipid bilayer substrate are studied using a molecular level theory of lipid chain packing in membranes. The peptides are modeled as "amphipathic cylinders" characterized by a well-defined polar angle. Assuming two-dimensional nematic order of the adsorbed peptides, the membrane perturbation free energy is evaluated using a cell-like model;...
The Function and Development of Soybean Peptides
Institute of Scientific and Technical Information of China (English)
Yang Caiyan; Song Junmei
Soybean peptides are small molecules hydrolyzed soy protein,from three to six amino acid composition of the peptide mixture,in 1000Da molecular weight below.Because it has a lot of good physical and chemical properties and physiological functions,in many areas has been widely used.This paper reviews the soybean peptide physical and chemical characteristics,physiological functions,technology and applications in the food industry.
Antimicrobial peptides in human skin disease
Kenshi, Yamasaki; Richard, L. Gallo
The skin continuously encounters microbial pathogens. To defend against this, cells of the epidermis and dermis have evolved several innate strategies to prevent infection. Antimicrobial peptides are one of the primary mechanisms used by the skin in the early stages of immune defense. In general, antimicrobial peptides have broad antibacterial activity against gram-positive and negative bacteria and also show antifungal and antiviral activity. The antimicrobial activity of most peptides occur...
Production of peptide antisera specific for mouse and rat proinsulin C-peptide 2
DEFF Research Database (Denmark)
Blume, N; Madsen, O D; Kofod, Hans;
Mice and rats have two functional non-allelic insulin genes. By using a synthetic peptide representing a common sequence in mouse and rat C-peptide 2 as antigen, we have produced rabbit antisera specific for an epitope which is not present in mouse or rat C-peptide 1. Long-term immunization did n...
Peptide Nucleic Acids Complexes of Two Peptide Nucleic Acid Strands and One
DEFF Research Database (Denmark)
Peptide nucleic acids and analogues of peptide nucleic acids are used to form duplex, triplex, and other structures with nucleic acids and to modify nucleic acids. The peptide nucleic acids and analogues thereof also are used to modulate protein activity through, for example, transcription arrest...
Mechanism and kinetics of peptide partitioning into membranes from all-atom simulations of thermostable peptides
Ulmschneider, Martin B.; Doux, Jacques P F; Killian, J. Antoinette; Smith, Jeremy C.; Ulmschneider, Jakob P.
Partitioning properties of transmembrane (TM) polypeptide segments directly determine membrane protein folding, stability, and function, and their understanding is vital for rational design of membrane active peptides. However, direct determination of water-to-bilayer transfer of TM peptides has proved difficult. Experimentally, sufficiently hydrophobic peptides tend to aggregate, while atomistic computer simulations at physiological temperatures cannot yet reach the long time scales required...
Synthetic peptide vaccines: palmitoylation of peptide antigens by a thioester bond increases immunogenicity
DEFF Research Database (Denmark)
Beekman, N.J.C.M.; Schaaper, W.M.M.; Tesser, G.I.;
amide bond. It was found that these S-palmitoylated peptides were much more immunogenic than N-palmitoylated peptides and at least similar to KLH-conjugated peptides with respect to appearance and magnitude of induced antibodies (canine parvovirus) or immunocastration effect (gonadotropin...
Atrial natriuretic peptides in plasma
DEFF Research Database (Denmark)
Goetze, Jens P; Holst Hansen, Lasse; Terzic, Dijana;
Measurement of cardiac natriuretic peptides in plasma has gained a diagnostic role in the assessment of heart failure. Plasma measurement is though hampered by the marked instability of the hormones, which has led to the development of analyses that target N-terminal fragments from the prohormone....... These fragments are stable in plasma and represent surrogate markers of the actual natriuretic hormone. Post-translational processing of the precursors, however, is revealing itself to be a complex event with new information still being reported on proteolysis, covalent modifications, and amino acid...
DEFF Research Database (Denmark)
Deacon, C F; Holst, Jens Juul; Carr, R D
Type 2 diabetes mellitus is a metabolic disease resulting in raised blood sugar which, if not satisfactorily controlled, can cause severe and often debilitating complications. Unfortunately, for many patients, the existing therapies do not give adequate control. Glucagon-like peptide-1 (GLP-1) is...... an incretin hormone which has a spectrum of activities which oppose the symptoms of diabetes. Of particular significance is the fact that these actions are glucose-dependent, meaning that the risk of severe hypoglycemia is practically eliminated. The recent elucidation of the key role of dipeptidyl...
Askenazi, Manor; Ruggles, Kelly V; Fenyö, David
Every molecular player in the cast of biology's central dogma is being sequenced and quantified with increasing ease and coverage. To bring the resulting genomic, transcriptomic, and proteomic data sets into coherence, tools must be developed that do not constrain data acquisition and analytics in any way but rather provide simple links across previously acquired data sets with minimal preprocessing and hassle. Here we present such a tool: PGx, which supports proteogenomic integration of mass spectrometry proteomics data with next-generation sequencing by mapping identified peptides onto their putative genomic coordinates. PMID:26638927
Natriuretic peptides and their therapeutic potential.
Cho, Y; Somer, B G; Amatya, A
Natriuretic peptides are a group of naturally occurring substances that act in the body to oppose the activity of the renin-angiotensin system. There are three major natriuretic peptides: atrial natriuretic peptide (ANP), which is synthesized in the atria; brain natriuretic peptide (BNP), which is synthesized in the ventricles; and C-type natriuretic peptide (CNP), which is synthesized in the brain. Both ANP and BNP are released in response to atrial and ventricular stretch, respectively, and will cause vasorelaxation, inhibition of aldosterone secretion in the adrenal cortex, and inhibition of renin secretion in the kidney. Both ANP and BNP will cause natriuresis and a reduction in intravascular volume, effects amplified by antagonism of antidiuretic hormone (ADH). The physiologic effects of CNP are different from those of ANP and BNP. CNP has a hypotensive effect, but no significant diuretic or natriuretic actions. Three natriuretic peptide receptors (NPRs) have been described that have different binding capacities for ANP, BNP, and CNP. Removal of the natriuretic peptides from the circulation is affected mainly by binding to clearance receptors and enzymatic degradation in the circulation. Increased blood levels of natriuretic peptides have been found in certain disease states, suggesting a role in the pathophysiology of those diseases, including congestive heart failure (CHF), systemic hypertension, and acute myocardial infarction. The natriuretic peptides also serve as disease markers and indicators of prognosis in various cardiovascular conditions. The natriuretic peptides have been used in the treatment of disease, with the most experience with intravenous BNP in the treatment of CHF. Another pharmacologic approach being used is the inhibition of natriuretic peptide metabolism by neutral endopeptidase (NEP) inhibitor drugs. The NEP inhibitors are currently being investigated as treatments for CHF and systemic hypertension. PMID:11720638
Driving engineering of novel antimicrobial peptides from simulations of peptide-micelle interactions
DEFF Research Database (Denmark)
Khandelia, Himanshu; Langham, Allison A; Kaznessis, Yiannis N
Simulations of antimicrobial peptides in membrane mimics can provide the high resolution, atomistic picture that is necessary to decipher which sequence and structure components are responsible for activity and toxicity. With such detailed insight, engineering new sequences that are active but non...... peptides and their interaction with membrane mimics. In this article, we discuss the promise and the challenges of widely used models and detail our recent work on peptide-micelle simulations as an attractive alternative to peptide-bilayer simulations. We detail our results with two large structural...... classes of peptides, helical and beta-sheet and demonstrate how simulations can assist in engineering of novel antimicrobials with therapeutic potential....
Determination of peptide content of DOTA-peptides by metal titration and UPLC
International Nuclear Information System (INIS)
Radiolabelled DOTA-peptides are in use for Peptide Receptor Radionuclide Scintigraphy (PRS) and Therapy (PRRT), e.g with 177Lu-DOTA-TATE or 90Y-DOTATOC. Labelling conditions are frequently critical. Therefore, the ingredients of the reaction, e.g. radiometal (90Y and 177Lu) and DOTA-peptide should be pure and the content known. Quality control of DOTA-peptide, can be performed with various methods, most commonly by UV. There are numerous conditions in which this is hampered, e.g. impurities may also have UV-absorption. The aim of the study was to quantify content and purity of DOTA-peptide
Antioxidant activity of yoghurt peptides: Part 2 – Characterisationof peptide fractions
DEFF Research Database (Denmark)
Farvin, Sabeena; Baron, Caroline; Nielsen, Nina Skall; Otte, Jeanette; Jacobsen, Charlotte
The aim of the present study was to elucidate previous findings showing that peptide fractions isolated from yoghurt had antioxidant effects. Therefore, peptides and free amino acids released during fermentation of milk were characterised. Yoghurt samples were stripped from sugars and lactic acid...... all the peptides identified contained at least one proline residue. Some of the identified peptides included the hydrophobic amino acid residues Val or Leu at the N-terminus and Pro, His or Tyr in the amino acid sequence, which is characteristic of antioxidant peptides. In addition, the yoghurt...
Trandermal Peptides for Large Molecule Delivery
Institute of Scientific and Technical Information of China (English)
@@ A research team, led by Prof. WEN Longping from the University of Science and Technology of China under CAS,has successfully screened out a trandermal peptide, using biotechnology. The new peptide is able to deliver insulin into human body through skin, rendering an immediate therapeutic effect. The finding was published in the March 27 issue of the journal Natural Biotechnology.
Protein identification by peptide mass fingerprinting
DEFF Research Database (Denmark)
Hjernø, Karin
Peptide mass fingerprinting is an effective way of identifying, e.g., gel-separated proteins, by matching experimentally obtained peptide mass data against large databases. However, several factors are known to influence the quality of the resulting matches, such as proteins contaminating the...
Peptide Mass Fingerprinting of Egg White Proteins
Alty, Lisa T.; LaRiviere, Frederick J.
Use of advanced mass spectrometry techniques in the undergraduate setting has burgeoned in the past decade. However, relatively few undergraduate experiments examine the proteomics tools of protein digestion, peptide accurate mass determination, and database searching, also known as peptide mass fingerprinting. In this experiment, biochemistry…
Engineered Adhesion Peptides for Improved Silicon Adsorption.
Ramakrishnan, Sathish Kumar; Jebors, Said; Martin, Marta; Cloitre, Thierry; Agarwal, Vivechana; Mehdi, Ahmad; Martinez, Jean; Subra, Gilles; Gergely, Csilla
Engineering peptides that present selective recognition and high affinity for a material is a major challenge for assembly-driven elaboration of complex systems with wide applications in the field of biomaterials, hard-tissue regeneration, and functional materials for therapeutics. Peptide-material interactions are of vital importance in natural processes but less exploited for the design of novel systems for practical applications because of our poor understanding of mechanisms underlying these interactions. Here, we present an approach based on the synthesis of several truncated peptides issued from a silicon-specific peptide recovered via phage display technology. We use the photonic response provided by porous silicon microcavities to evaluate the binding efficiency of 14 different peptide derivatives. We identify and engineer a short peptide sequence (SLVSHMQT), revealing the highest affinity for p(+)-Si. The molecular recognition behavior of the obtained peptide fragment can be revealed through mutations allowing identification of the preferential affinity of certain amino acids toward silicon. These results constitute an advance in both the engineering of peptides that reveal recognition properties for silicon and the understanding of biomolecule-material interactions. PMID:26440047
Milk proteins as precursors of bioactive peptides
Directory of Open Access Journals (Sweden)
Marta Dziuba
Full Text Available Milk proteins, a source of bioactive peptides, are the subject of numerous research studies aiming to, among others, evaluate their properties as precursors of biologically active peptides. Physiologically active peptides released from their precursors may interact with selected receptors and affect the overall condition and health of humans. By relying on the BIOPEP database of proteins and bioactive peptides, developed by the Department of Food Biochemistry at the University of Warmia and Mazury in Olsztyn (www.uwm.edu.pl/biochemia, the profiles of potential activity of milk proteins were determined and the function of those proteins as bioactive peptide precursors was evaluated based on a quantitative criterion, i.e. the occurrence frequency of bioactive fragments (A. The study revealed that milk proteins are mainly a source of peptides with the following types of activity: antihypertensive (Amax = 0.225, immunomodulating (0.024, smooth muscle contracting (0.011, antioxidative (0.029, dipeptidyl peptidase IV inhibitors (0.148, opioid (0.073, opioid antagonistic (0.053, bonding and transporting metals and metal ions (0.024, antibacterial and antiviral (0.024, and antithrombotic (0.029. The enzymes capable of releasing bioactive peptides from precursor proteins were determined for every type of activity. The results of the experiment indicate that milk proteins such as lactoferrin, α-lactalbumin, β-casein and κ-casein hydrolysed by trypsin can be a relatively abundant source of biologically active peptides.
Peptide nanospheres self-assembled from a modified β-annulus peptide of Sesbania mosaic virus.
Matsuura, Kazunori; Mizuguchi, Yusaku; Kimizuka, Nobuo
A novel β-annulus peptide of Sesbania mosaic virus bearing an FKFE sequence at the C terminus was synthesized, and its self-assembling behavior in water was investigated. Dynamic light scattering and transmission electron microscopy showed that the β-annulus peptide bearing an FKFE sequence self-assembled into approximately 30 nm nanospheres in water at pH 3.8, whereas the β-annulus peptide without the FKFE sequence afforded only irregular aggregates. The peptide nanospheres possessed a definite critical aggregation concentration (CAC = 26 μM), above which the size of nanospheres were nearly unaffected by the peptide concentration. The formation of peptide nanospheres was significantly affected by pH; the peptide did not form any assemblies at pH 2.2, whereas larger aggregates were formed at pH 6.4-11.6. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 470-475, 2016. PMID:26573103
Interpreting peptide mass spectra by VEMS
DEFF Research Database (Denmark)
Mathiesen, Rune; Lundsgaard, M.; Welinder, Karen G.;
Most existing Mass Spectra (MS) analysis programs are automatic and provide limited opportunity for editing during the interpretation. Furthermore, they rely entirely on publicly available databases for interpretation. VEMS (Virtual Expert Mass Spectrometrist) is a program for interactive analysis...... of peptide MS/MS spectra imported in text file format. Peaks are annotated, the monoisotopic peaks retained, and the b-and y-ion series identified in an interactive manner. The called peptide sequence is searched against a local protein database for sequence identity and peptide mass. The report...... compares the calculated and the experimental mass spectrum of the called peptide. The program package includes four accessory programs. VEMStrans creates protein databases in FASTA format from EST or cDNA sequence files. VEMSdata creates a virtual peptide database from FASTA files. VEMSdist displays the...
Intracellular signalling by C-peptide.
Hills, Claire E; Brunskill, Nigel J
C-peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C-peptide when administered to individuals with type I diabetes. Data indicate that C-peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G-protein coupled. Binding of C-peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI-3-kinase activity, stimulation of the Na(+)/K(+) ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C-peptide may serve as a potential therapeutic agent for the treatment or prevention of long-term complications associated with diabetes. PMID:18382618
Intracellular Signalling by C-Peptide
Directory of Open Access Journals (Sweden)
Claire E. Hills
Full Text Available C-peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C-peptide when administered to individuals with type I diabetes. Data indicate that C-peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G-protein coupled. Binding of C-peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI-3-kinase activity, stimulation of the Na+/K+ ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C-peptide may serve as a potential therapeutic agent for the treatment or prevention of long-term complications associated with diabetes.
Insights into How Cyclic Peptides Switch Conformations.
McHugh, Sean M; Rogers, Julia R; Yu, Hongtao; Lin, Yu-Shan
Cyclic peptides have recently emerged as promising modulators of protein-protein interactions. However, it is currently highly difficult to predict the structures of cyclic peptides owing to their rugged conformational free energy landscape, which prevents sampling of all thermodynamically relevant conformations. In this article, we first investigate how a relatively flexible cyclic hexapeptide switches conformations. It is found that, although the circular geometry of small cyclic peptides of size 6-8 may require rare, coherent dihedral changes to sample a new conformation, the changes are rather local, involving simultaneous changes of ϕi and ψi or ψi and ϕi+1. The understanding of how these cyclic peptides switch conformations enables the use of metadynamics simulations with reaction coordinates specifically targeting such coupled two-dihedral changes to effectively sample cyclic peptide conformational space. PMID:27031286
Radiolabeled peptides: experimental and clinical applications
International Nuclear Information System (INIS)
Radiolabeled receptor specific biomolecules hold unlimited potential in nuclear medicine. During the past few years much attention has been drawn to the development radiolabeled peptides for a variety of diagnostic applications, as well as for therapy of malignant tumors. Although only one peptide, In-111-DTPA-(D)-Phe1-octreotide, is available commercially for oncologic imaging, many more have been examined in humans with hematological disorders, and the early results appear to be promising. Impetus generated by these results have prompted investigators to label peptides with such radionuclides as Tc-99m, I-123, F-18, Cu-64, and Y-90. This review is intended to highlight the qualities of peptides, summarize the clinical results, and address some important issues associated with radiolabeling of highly potent peptides. While doing so, various methods of radiolabeling have been described, and their strengths and weaknesses have also been discussed. (author)
Peptide-Lipid Interactions: Experiments and Applications
Directory of Open Access Journals (Sweden)
Massimiliano Galdiero
Full Text Available The interactions between peptides and lipids are of fundamental importance in the functioning of numerous membrane-mediated cellular processes including antimicrobial peptide action, hormone-receptor interactions, drug bioavailability across the blood-brain barrier and viral fusion processes. Moreover, a major goal of modern biotechnology is obtaining new potent pharmaceutical agents whose biological action is dependent on the binding of peptides to lipid-bilayers. Several issues need to be addressed such as secondary structure, orientation, oligomerization and localization inside the membrane. At the same time, the structural effects which the peptides cause on the lipid bilayer are important for the interactions and need to be elucidated. The structural characterization of membrane active peptides in membranes is a harsh experimental challenge. It is in fact accepted that no single experimental technique can give a complete structural picture of the interaction, but rather a combination of different techniques is necessary.
Novel Bifunctional Natriuretic Peptides as Potential Therapeutics*
Dickey, Deborah M.; Burnett, John C.; Potter, Lincoln R.
Synthetic atrial natriuretic peptide (carperitide) and B-type natriuretic peptide (BNP; nesiritide) are used to treat congestive heart failure. However, despite beneficial cardiac unloading properties, reductions in renal perfusion pressures limit their clinical effectiveness. Recently, CD-NP, a chimeric peptide composed of C-type natriuretic peptide (CNP) fused to the C-terminal tail of Dendroaspis natriuretic peptide (DNP), was shown to be more glomerular filtration rate-enhancing than BNP in dogs. However, the molecular basis for the increased responsiveness was not determined. Here, we show that the DNP tail has a striking effect on CNP, converting it from a non-agonist to a partial agonist of natriuretic peptide receptor (NPR)-A while maintaining the ability to activate NPR-B. This effect is specific for human receptors because CD-NP was only a slightly better activator of rat NPR-A due to the promiscuous nature of CNP in this species. Interesting, the DNP tail alone had no effect on any NPR even though it is effective in vivo. To further increase the potency of CD-NP for NPR-A, we converted two different triplet sequences within the CNP ring to their corresponding residues in BNP. Both variants demonstrated increased affinity and full agonist activity for NPR-A, whereas one was as potent as any NPR-A activator known. In contrast to a previous report, we found that DNP binds the natriuretic peptide clearance receptor (NPR-C). However, none of the chimeric peptides bound NPR-C with significantly higher affinity than endogenous ligands. We suggest that bifunctional chimeric peptides represent a new generation of natriuretic peptide therapeutics. PMID:18940797
Novel bifunctional natriuretic peptides as potential therapeutics.
Dickey, Deborah M; Burnett, John C; Potter, Lincoln R
Synthetic atrial natriuretic peptide (carperitide) and B-type natriuretic peptide (BNP; nesiritide) are used to treat congestive heart failure. However, despite beneficial cardiac unloading properties, reductions in renal perfusion pressures limit their clinical effectiveness. Recently, CD-NP, a chimeric peptide composed of C-type natriuretic peptide (CNP) fused to the C-terminal tail of Dendroaspis natriuretic peptide (DNP), was shown to be more glomerular filtration rate-enhancing than BNP in dogs. However, the molecular basis for the increased responsiveness was not determined. Here, we show that the DNP tail has a striking effect on CNP, converting it from a non-agonist to a partial agonist of natriuretic peptide receptor (NPR)-A while maintaining the ability to activate NPR-B. This effect is specific for human receptors because CD-NP was only a slightly better activator of rat NPR-A due to the promiscuous nature of CNP in this species. Interesting, the DNP tail alone had no effect on any NPR even though it is effective in vivo. To further increase the potency of CD-NP for NPR-A, we converted two different triplet sequences within the CNP ring to their corresponding residues in BNP. Both variants demonstrated increased affinity and full agonist activity for NPR-A, whereas one was as potent as any NPR-A activator known. In contrast to a previous report, we found that DNP binds the natriuretic peptide clearance receptor (NPR-C). However, none of the chimeric peptides bound NPR-C with significantly higher affinity than endogenous ligands. We suggest that bifunctional chimeric peptides represent a new generation of natriuretic peptide therapeutics. PMID:18940797
Modelling water molecules inside cyclic peptide nanotubes
Tiangtrong, Prangsai; Thamwattana, Ngamta; Baowan, Duangkamon
Cyclic peptide nanotubes occur during the self-assembly process of cyclic peptides. Due to the ease of synthesis and ability to control the properties of outer surface and inner diameter by manipulating the functional side chains and the number of amino acids, cyclic peptide nanotubes have attracted much interest from many research areas. A potential application of peptide nanotubes is their use as artificial transmembrane channels for transporting ions, biomolecules and waters into cells. Here, we use the Lennard-Jones potential and a continuum approach to study the interaction of a water molecule in a cyclo[(- D-Ala- L-Ala)_4-] peptide nanotube. Assuming that each unit of a nanotube comprises an inner and an outer tube and that a water molecule is made up of a sphere of two hydrogen atoms uniformly distributed over its surface and a single oxygen atom at the centre, we determine analytically the interaction energy of the water molecule and the peptide nanotube. Using this energy, we find that, independent of the number of peptide units, the water molecule will be accepted inside the nanotube. Once inside the nanotube, we show that a water molecule prefers to be off-axis, closer to the surface of the inner nanotube. Furthermore, our study of two water molecules inside the peptide nanotube supports the finding that water molecules form an array of a 1-2-1-2 file inside peptide nanotubes. The theoretical study presented here can facilitate thorough understanding of the behaviour of water molecules inside peptide nanotubes for applications, such as artificial transmembrane channels.
The novel amyloid-beta peptide aptamer inhibits intracellular amyloid-beta peptide toxicity
Institute of Scientific and Technical Information of China (English)
Xu Wang; Yi Yang; Mingyue Jia; Chi Ma; Mingyu Wang; Lihe Che; Yu Yang; Jiang Wu
Amyloid β peptide binding alcohol dehydrogenase (ABAD) decoy peptide (DP) can competitively antagonize binding of amyloid β peptide to ABAD and inhibit the cytotoxic effects of amyloid β peptide. Based on peptide aptamers, the present study inserted ABAD-DP into the disulfide bond of human thioredoxin (TRX) using molecular cloning technique to construct a fusion gene that can express the TRX1-ABAD-DP-TRX2 aptamer. Moreover, adeno-associated virus was used to allow its stable expression. Immunofluorescent staining revealed the co-expression of the transduced fusion gene TRX1-ABAD-DP-TRX2 and amyloid β peptide in NIH-3T3 cells, indicating that the TRX1-ABAD-DP-TRX2 aptamer can bind amyloid β peptide within cells. In addition, cell morphology and MTT results suggested that TRX1-ABAD-DP-TRX2 attenuated amyloid β peptide-induced SH-SY5Y cell injury and improved cell viability. These findings confirmed the possibility of constructing TRX-based peptide aptamer using ABAD-DP. Moreover, TRX1-ABAD-DP-TRX2 inhibited the cytotoxic effect of amyloid β peptide.
Interactions of Bio-Inspired Membranes with Peptides and Peptide-Mimetic Nanoparticles
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Michael Sebastiano
Full Text Available Via Dissipative Particle Dynamics (DPD and implicit solvent coarse-grained (CG Molecular Dynamics (MD we examine the interaction of an amphiphilic cell-penetrating peptide PMLKE and its synthetic counterpart with a bio-inspired membrane. We use the DPD technique to investigate the interaction of peptide-mimetic nanoparticles, or nanopins, with a three-component membrane. The CG MD approach is used to investigate the interaction of a cell-penetrating peptide PMLKE with single-component membrane. We observe the spontaneous binding and subsequent insertion of peptide and nanopin in the membrane by using CG MD and DPD approaches, respectively. In addition, we find that the insertion of peptide and nanopins is mainly driven by the favorable enthalpic interactions between the hydrophobic components of the peptide, or nanopin, and the membrane. Our study provides insights into the mechanism underlying the interactions of amphiphilic peptide and peptide-mimetic nanoparticles with a membrane. The result of this study can be used to guide the functional integration of peptide and peptide-mimetic nanoparticles with a cell membrane.
Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides
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Vegt, Erik; Eek, Annemarie; Oyen, Wim J.G.; Gotthardt, Martin; Boerman, Otto C. [Radboud University Nijmegen Medical Centre, Department of Nuclear Medicine (444), PO Box 9101, Nijmegen (Netherlands); Jong, Marion de [Erasmus Medical Centre, Department of Nuclear Medicine, Rotterdam (Netherlands)
In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of {sup 111}In-albumin, {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide was determined. FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of {sup 111}In-albumin, {sup 111}In-exendin and {sup 111}In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide 6), was selected for in vivo testing. In rats, 5 mg of peptide 6 very efficiently inhibited the renal uptake of {sup 111}In-minigastrin, by 88%. Uptake of {sup 111}In-exendin and {sup 111}In-octreotide was reduced by 26 and 33%, respectively. The albumin-derived peptide 6 efficiently inhibited the renal reabsorption of {sup 111}In-minigastrin, {sup 111}In-exendin and {sup 111}In-octreotide and is a promising candidate for kidney protection in PRRT. (orig.)
Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides
International Nuclear Information System (INIS)
In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of 111In-albumin, 111In-minigastrin, 111In-exendin and 111In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of 111In-minigastrin, 111In-exendin and 111In-octreotide was determined. FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of 111In-albumin, 111In-exendin and 111In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide 6), was selected for in vivo testing. In rats, 5 mg of peptide 6 very efficiently inhibited the renal uptake of 111In-minigastrin, by 88%. Uptake of 111In-exendin and 111In-octreotide was reduced by 26 and 33%, respectively. The albumin-derived peptide 6 efficiently inhibited the renal reabsorption of 111In-minigastrin, 111In-exendin and 111In-octreotide and is a promising candidate for kidney protection in PRRT. (orig.)
rapmad: Robust analysis of peptide microarray data
Directory of Open Access Journals (Sweden)
Rothermel Andrée
Full Text Available Abstract Background Peptide microarrays offer an enormous potential as a screening tool for peptidomics experiments and have recently seen an increased field of application ranging from immunological studies to systems biology. By allowing the parallel analysis of thousands of peptides in a single run they are suitable for high-throughput settings. Since data characteristics of peptide microarrays differ from DNA oligonucleotide microarrays, computational methods need to be tailored to these specifications to allow a robust and automated data analysis. While follow-up experiments can ensure the specificity of results, sensitivity cannot be recovered in later steps. Providing sensitivity is thus a primary goal of data analysis procedures. To this end we created rapmad (Robust Alignment of Peptide MicroArray Data, a novel computational tool implemented in R. Results We evaluated rapmad in antibody reactivity experiments for several thousand peptide spots and compared it to two existing algorithms for the analysis of peptide microarrays. rapmad displays competitive and superior behavior to existing software solutions. Particularly, it shows substantially improved sensitivity for low intensity settings without sacrificing specificity. It thereby contributes to increasing the effectiveness of high throughput screening experiments. Conclusions rapmad allows the robust and sensitive, automated analysis of high-throughput peptide array data. The rapmad R-package as well as the data sets are available from http://www.tron-mz.de/compmed.
Conus Peptides A Rich Pharmaceutical Treasure
Institute of Scientific and Technical Information of China (English)
Cheng-Zhong WANG; Cheng-Wu CHI
Marine predatory cone snails (genus Conus) with over 500 species represent what is arguably the largest single genus of marine animals alive today. All Conus are venomous and utilize a complex mixture of Conus peptides to capture their preys and for other biological purposes. Each component of Conus peptides selectively targets a specific subtype of ion channels, neurotransmitter receptors or transporters.Owing to their diversity, more than 50,000 distinct active peptides are theoretically estimated in Conus venoms. These diversified toxins are generally categorized into several superfamilies and/or families based on their characteristic arrangements of cysteine residues and pharmacological actions. Some mechanisms underlying the remarkable diversity of Conus peptides have been postulated: the distinctive gene structure, gene duplication and/or allelic selection, genus speciation, and sophisticated expression pattern and posttranslational modification of these peptides. Due to their highly pharmacological potency and target selectivity, Conus peptides have attracted extensive attention with their potentials to be developed as new research tools in neuroscience field and as novel medications in clinic for pain, epilepsy and other neuropathic disorders. Several instructive lessons for our drug development could be also learnt from these neuropharmacological "expertises". Conus peptides comprise a rich resource for neuropharmacologists, and most of them await to be explored.
C-Peptide and its intracellular signaling.
Hills, Claire E; Brunskill, Nigel J
Although long believed to be inert, C-peptide has now been shown to have definite biological effects both in vitro and in vivo in diabetic animals and in patients with type 1 diabetes. These effects point to a protective action of C-peptide against the development of diabetic microvascular complications. Underpinning these observations is undisputed evidence of C-peptide binding to a variety of cell types at physiologically relevant concentrations, and the downstream stimulation of multiple cell signaling pathways and gene transcription via the activation of numerous transcription factors. These pathways affect such fundamental cellular processes as re-absorptive and/or secretory phenotype, migration, growth, and survival. Whilst the receptor remains to be identified, experimental data points strongly to the existence of a specific G-protein-coupled receptor for C-peptide. Of the cell types studied so far, kidney tubular cells express the highest number of C-peptide binding sites. Accordingly, C-peptide exerts major effects on the function of these cells, and in the context of diabetic nephropathy appears to antagonise the pathophysiological effects of major disease mediators such as TGFbeta1 and TNFalpha. Therefore, based on its cellular activity profile C-peptide appears well positioned for development as a therapeutic tool to treat microvascular complications in type 1 diabetes. PMID:20039003
Novel pH-Sensitive Cyclic Peptides.
Weerakkody, Dhammika; Moshnikova, Anna; El-Sayed, Naglaa Salem; Adochite, Ramona-Cosmina; Slaybaugh, Gregory; Golijanin, Jovana; Tiwari, Rakesh K; Andreev, Oleg A; Parang, Keykavous; Reshetnyak, Yana K
A series of cyclic peptides containing a number of tryptophan (W) and glutamic acid (E) residues were synthesized and evaluated as pH-sensitive agents for targeting of acidic tissue and pH-dependent cytoplasmic delivery of molecules. Biophysical studies revealed the molecular mechanism of peptides action and localization within the lipid bilayer of the membrane at high and low pHs. The symmetric, c[(WE)4WC], and asymmetric, c[E4W5C], cyclic peptides translocated amanitin, a polar cargo molecule of similar size, across the lipid bilayer and induced cell death in a pH- and concentration-dependent manner. Fluorescently-labelled peptides were evaluated for targeting of acidic 4T1 mammary tumors in mice. The highest tumor to muscle ratio (5.6) was established for asymmetric cyclic peptide, c[E4W5C], at 24 hours after intravenous administration. pH-insensitive cyclic peptide c[R4W5C], where glutamic acid residues (E) were replaced by positively charged arginine residues (R), did not exhibit tumor targeting. We have introduced a novel class of cyclic peptides, which can be utilized as a new pH-sensitive tool in investigation or targeting of acidic tissue. PMID:27515582
Natriuretic peptides in cardiometabolic regulation and disease
DEFF Research Database (Denmark)
Zois, Nora E; Bartels, Emil D; Hunter, Ingrid; Kousholt, Birgitte S; Olsen, Lars Henning; Goetze, Jens P
decade. Dysregulation of the natriuretic peptide system has been associated with obesity, glucose intolerance, type 2 diabetes mellitus, and essential hypertension. Moreover, the natriuretic peptides have been implicated in the protection against atherosclerosis, thrombosis, and myocardial ischaemia. All......In the 30 years since the identification of the natriuretic peptides, their involvement in regulating fluid and blood pressure has become firmly established. Data indicating a role for these hormones in lifestyle-related metabolic and cardiovascular disorders have also accumulated over the past...... role in lifestyle-related metabolic and cardiovascular disorders....
Imaging tumors with peptide-based radioligands
Energy Technology Data Exchange (ETDEWEB)
Behr, T. M.; Gotthardt, M.; Barth, A.; Behe, M. [Philipps-University of Marburg, Dept. of Nuclear Medicine, Marburg (Germany)
Regulatory peptides are small, readily diffusable and potent natural substances with a wide spectrum of receptor-mediated actions in humans. High affinity receptors for these peptides are (over)-expressed in many neoplasms, and these receptors may represent, therefore, new molecular targets for cancer diagnosis and therapy. This review aims to give an overview of the peptide-based radiopharmaceuticals which are presently already commercially available or which are in advanced stages of their clinical testing so that their broader availability is anticipated soon. Physiologically, these peptides bind to and act through G protein-coupled receptors in the cell membrane. Historically, somatostatin analogs are the first class of receptor binding peptides having gained clinical application. In {sup 111}In-DTPA-(D-Phe{sup 1})-octreotide is the first and only radio peptide which has obtained regulatory approval in Europe and the United States to date. Extensive clinical studies involving several thousands of patients have shown that the major clinical application of somatostatin receptor scintigraphy is the detection and the staging of gastroenteropancreatic neuroendocrine tumors (carcinoids). In these tumors, octreotide scintigraphy is superior to any other staging method. However, its sensitivity and accuracy in other, more frequent neoplasms is limited. Radiolabeled vasoactive intestinal peptide (VIP) has been shown to visualize the majority of gastrointestinal adenocarcinomas, as well as some neuroendocrine tumors, including insulinomas (the latter being often missed by somatostatin receptor scintigraphy). Due to the outstanding diagnostic accuracy of the pentagastrin test in detecting the presence, persistence, or recurrence of medullary thyroid cancer (MTC), it was postulated the expression of the corresponding (i.e. cholecystokinin (CCK-)-B) receptor type in human MTC. This receptor is also widely expressed on human small-cell lung. Indeed, {sup 111}In-labeled DTPA
Peptides from milk proteins and their properties.
Kilara, Arun; Panyam, Dinakar
This review has attempted to study the literature pertaining to peptides derived from milk proteins. Hydrolysis of milk proteins to generate peptides has been practiced for a long time and it was recognized early on in this process that the taste of hydrolyzates might hinder use of these products in food formulations. Modification of protein is necessary to form a more acceptable or utilizable product, to form a product that is less susceptible to deteriorative reactions and to form a product that is of higher nutritionall quality. Modifications may be achieved by a number of chemical and enzymatic means. This review has considered only enzymatic modification of dairy proteins. Modified proteins contain peptides and some of these peptides have been purified and their functionalities have been compared with unmodified proteins. This paper has examined the literature pertaining to improvement in functionality of enzyme-modified proteins. Improvements in solubility, emulsification, foaming and gelation were examined. There is limited information available on the sequence of the peptides necessary to improve the functional characteristics of proteins. Knowing the sequences of desirable functional peptides can lead to genetic alteration of proteins to improve functionality. Addition of synthetic peptides to intact proteins may be another way in which the functionality of proteins can be augmented. Some of the peptides in milk proteins are capable of affecting biological functions of an organism. These effects can be antimicrobial and probiotic, i.e., prevent the growth and proliferation of undesirable and pathogenic organisms, or they may promote the growth of desirable bacteria in the digestive tract of humans and animals. Peptides derived from milk protein have been shown to exert digestive and metabolic effects as well. They may also influence the immune system. These biological effects may play an important role in the development of medical foods that treat or
Exploiting Protected Maleimides to Modify Oligonucleotides, Peptides and Peptide Nucleic Acids
Directory of Open Access Journals (Sweden)
Clément Paris
Full Text Available This manuscript reviews the possibilities offered by 2,5-dimethylfuran-protected maleimides. Suitably derivatized building blocks incorporating the exo Diels-Alder cycloadduct can be introduced at any position of oligonucleotides, peptide nucleic acids, peptides and peptoids, making use of standard solid-phase procedures. Maleimide deprotection takes place upon heating, which can be followed by either Michael-type or Diels-Alder click conjugation reactions. However, the one-pot procedure in which maleimide deprotection and conjugation are simultaneously carried out provides the target conjugate more quickly and, more importantly, in better yield. This procedure is compatible with conjugates involving oligonucleotides, peptides and peptide nucleic acids. A variety of cyclic peptides and oligonucleotides can be obtained from peptide and oligonucleotide precursors incorporating protected maleimides and thiols.
Combined Statistical Analyses of Peptide Intensities and Peptide Occurrences Improves Identification of Significant Peptides from MS-based Proteomics Data
Energy Technology Data Exchange (ETDEWEB)
Webb-Robertson, Bobbie-Jo M.; McCue, Lee Ann; Waters, Katrina M.; Matzke, Melissa M.; Jacobs, Jon M.; Metz, Thomas O.; Varnum, Susan M.; Pounds, Joel G.
Liquid chromatography-mass spectrometry-based (LC-MS) proteomics uses peak intensities of proteolytic peptides to infer the differential abundance of peptides/proteins. However, substantial run-to-run variability in peptide intensities and observations (presence/absence) of peptides makes data analysis quite challenging. The missing abundance values in LC-MS proteomics data are difficult to address with traditional imputation-based approaches because the mechanisms by which data are missing are unknown a priori. Data can be missing due to random mechanisms such as experimental error, or non-random mechanisms such as a true biological effect. We present a statistical approach that uses a test of independence known as a G-test to test the null hypothesis of independence between the number of missing values and the experimental groups. We pair the G-test results evaluating independence of missing data (IMD) with a standard analysis of variance (ANOVA) that uses only means and variances computed from the observed data. Each peptide is therefore represented by two statistical confidence metrics, one for qualitative differential observation and one for quantitative differential intensity. We use two simulated and two real LC-MS datasets to demonstrate the robustness and sensitivity of the ANOVA-IMD approach for assigning confidence to peptides with significant differential abundance among experimental groups.
Peptide Internalization Enabled by Folding: Triple Helical Cell-Penetrating Peptides
Shinde, Aparna; Feher, Katie M.; Hu, Chloe; Slowinska, Katarzyna
Cell-Penetrating Peptides (CPPs) are known as efficient transporters of molecular cargo across cellular membranes. Their properties make them ideal candidates for in vivo applications. However, challenges in development of effective CPPs still exist: CPPs are often fast degraded by proteases and large concentration of CPPs required for cargo transporting can cause cytotoxicity. It was previously shown that restricting peptide flexibility can improve peptide stability against enzymatic degrada...
A Peptide & Peptide Nucleic Acid Synthesis Technology for Transporter Molecules and Theranostics - The SPPS
Pipkorn, Ruediger; Braun, Klaus; Wiessler, Manfred; Waldeck, Waldemar; Schrenk, Hans-Hermann; Koch, Mario; Semmler, Wolfhard; Komljenovic, Dorde
Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and functi...
Collagen-like peptides and peptide-polymer conjugates in the design of assembled materials
Luo, Tianzhi; Kiick, Kristi L.
Collagen is the most abundant protein in mammals, and there has been long-standing interest in understanding and controlling collagen assembly in the design of new materials. Collagen-like peptides (CLP), also known as collagen-mimetic peptides (CMP) or collagen-related peptides (CRP), have thus been widely used to elucidate collagen triple helix structure as well as to produce higher-order structures that mimic natural collagen fibers. This mini-review provides an overview of recent progress...
Effect of peptide secondary structure on peptide amphiphile supramolecular structure and interactions
Missirlis, Dimitris; Chworos, Arkadiusz; Fu, Caroline J; Khant, Htet A.; Krogstad, Daniel V.; Tirrell, Matthew
Bottom-up fabrication of self-assembled nanomaterials requires control over forces and interactions between building blocks. We here report on the formation and architecture of supramolecular structures constructed from two different peptide amphiphiles. Inclusion of four alanines between a 16-mer peptide and a 16-carbon long aliphatic tail resulted in a secondary structure shift of the peptide headgroups from alpha helices to beta sheets. A concomitant shift in self-assembled morphology from...
A statistical approach to determining responses to individual peptides from pooled-peptide ELISpot data.
Ström, Peter; Støer, Nathalie; Borthwick, Nicola; Dong, Tao; Hanke, Tomáš; Reilly, Marie
To investigate in detail the effect of infection or vaccination on the human immune system, ELISpot assays are used to simultaneously test the immune response to a large number of peptides of interest. Scientists commonly use "peptide pools", where, instead of an individual peptide, a test well contains a group of peptides. Since the response from a well may be due to any or many of the peptides in the pool, pooled assays usually need to be followed by confirmatory assays of a number of individual peptides. We present a statistical method that enables estimation of individual peptide responses from pool responses using the Expectation Maximization (EM) algorithm for "incomplete data". We demonstrate the accuracy and precision of these estimates in simulation studies of ELISpot plates with 90 pools of 6 or 7 peptides arranged in three dimensions and three Mock wells for the estimation of background. In analysis of real pooled data from 6 subjects in a HIV-1 vaccine trial, where 199 peptides were arranged in 80 pools if size 9 or 10, our estimates were in very good agreement with the results from individual-peptide confirmatory assays. Compared to the classical approach, we could identify almost all the same peptides with high or moderate response, with less than half the number of confirmatory tests. Our method facilitates efficient use of the information available in pooled ELISpot data to avoid or reduce the need for confirmatory testing. We provide an easy-to-use free online application for implementing the method, where on uploading two spreadsheets with the pool design and pool responses, the user obtains the estimates of the individual peptide responses. PMID:27196788
Determination of peptide content and purity of DOTA-peptides by metal ion titration and UPLC. An alternative method to monitor quality of DOTA-peptides
International Nuclear Information System (INIS)
PRRT requires high specific activities, thus at low molar ratio between DOTA-peptide and radioactivity. Therefore, the ingredients of the reaction, including (radio)metals and DOTA-peptide must be pure and the content known. Our aim was to quantify content and purity of DOTA-peptide by a base-to-base separation of DOTA-peptide and metal-DOTA-peptide by UPLC and UV-detection. Quantification of these peaks reveals an accurate and sensitive method to quantify purity and content of DOTA-peptides. Moreover, this technique enables monitoring of the (radio)labeling process and co-introduction of impurities, including metal ions. (author)
Evolution of antimicrobial peptides to self-assembled peptides for biomaterial applications.
McCloskey, Alice P; Gilmore, Brendan F; Laverty, Garry
Biomaterial-related infections are a persistent burden on patient health, recovery, mortality and healthcare budgets. Self-assembled antimicrobial peptides have evolved from the area of antimicrobial peptides. Peptides serve as important weapons in nature, and increasingly medicine, for combating microbial infection and biofilms. Self-assembled peptides harness a "bottom-up" approach, whereby the primary peptide sequence may be modified with natural and unnatural amino acids to produce an inherently antimicrobial hydrogel. Gelation may be tailored to occur in the presence of physiological and infective indicators (e.g. pH, enzymes) and therefore allow local, targeted antimicrobial therapy at the site of infection. Peptides demonstrate inherent biocompatibility, antimicrobial activity, biodegradability and numerous functional groups. They are therefore prime candidates for the production of polymeric molecules that have the potential to be conjugated to biomaterials with precision. Non-native chemistries and functional groups are easily incorporated into the peptide backbone allowing peptide hydrogels to be tailored to specific functional requirements. This article reviews an area of increasing interest, namely self-assembled peptides and their potential therapeutic applications as innovative hydrogels and biomaterials in the prevention of biofilm-related infection. PMID:25436505
From a pro-apoptotic peptide to a lytic peptide: One single residue mutation.
Zhou, Xi-Rui; Zhang, Qiang; Tian, Xi-Bo; Cao, Yi-Meng; Liu, Zhu-Qing; Fan, Ruru; Ding, Xiu-Fang; Zhu, Zhentai; Chen, Long; Luo, Shi-Zhong
Further discovery and design of new anticancer peptides are important for the development of anticancer therapeutics, and study on the detailed acting mechanism and structure-function relationship of peptides is critical for anticancer peptide design and application. In this study, a novel anticancer peptide ZXR-1 (FKIGGFIKKLWRSKLA) derived from a known anticancer peptide mauriporin was developed, and a mutant ZXR-2 (FKIGGFIKKLWRSLLA) with only one residue difference at the 14th position (Lys→Leu) was also engineered. Replacement of the lysine with leucine made ZXR-2 more potent than ZXR-1 in general. Even with only one residue mutation, the two peptides displayed distinct anticancer modes of action. ZXR-1 could translocate into cells, target on the mitochondria and induce cell apoptosis, while ZXR-2 directly targeted on the cell membranes and caused membrane lysis. The variance in their acting mechanisms might be due to the different amphipathicity and positive charge distribution. In addition, the two Ile-Leu pairs (3-10 and 7-14) in ZXR-2 might also play a role in improving its cytotoxicity. Further study on the structure-function relationship of the two peptides may be beneficial for the design of novel anticancer peptides and peptide based therapeutics. PMID:27207743
Peptide binding specificity of the chaperone calreticulin
DEFF Research Database (Denmark)
Sandhu, N.; Duus, K.; Jorgensen, C.S.;
Calreticulin is a molecular chaperone with specificity for polypeptides and N-linked monoglucosylated glycans. In order to determine the specificity of polypeptide binding, the interaction of calreticulin with polypeptides was investigated using synthetic peptides of different length and composit...
Charge Transport Phenomena in Peptide Molecular Junctions
International Nuclear Information System (INIS)
Inelastic electron tunneling spectroscopy (IETS) is a valuable in situ spectroscopic analysis technique that provides a direct portrait of the electron transport properties of a molecular species. In the past, IETS has been applied to small molecules. Using self-assembled nano electronic junctions, IETS was performed for the first time on a large polypeptide protein peptide in the phosphorylated and native form, yielding interpretable spectra. A reproducible 10-fold shift of the I/V characteristics of the peptide was observed upon phosphorylation. Phosphorylation can be utilized as a site-specific modification to alter peptide structure and thereby influence electron transport in peptide molecular junctions. It is envisioned that kinases and phosphatases may be used to create tunable systems for molecular electronics applications, such as biosensors and memory devices.
Charge Transport Phenomena in Peptide Molecular Junctions
Directory of Open Access Journals (Sweden)
Alessandra Luchini
Full Text Available Inelastic electron tunneling spectroscopy (IETS is a valuable in situ spectroscopic analysis technique that provides a direct portrait of the electron transport properties of a molecular species. In the past, IETS has been applied to small molecules. Using self-assembled nanoelectronic junctions, IETS was performed for the first time on a large polypeptide protein peptide in the phosphorylated and native form, yielding interpretable spectra. A reproducible 10-fold shift of the I/V characteristics of the peptide was observed upon phosphorylation. Phosphorylation can be utilized as a site-specific modification to alter peptide structure and thereby influence electron transport in peptide molecular junctions. It is envisioned that kinases and phosphatases may be used to create tunable systems for molecular electronics applications, such as biosensors and memory devices.
Gene Transfer with Poly-Melittin Peptides
Chen, Chang-Po; Kim, Ji-Seon; Steenblock, Erin; Liu, Dijie; Rice, Kevin G.
The 26 amino acid hemolytic melittin peptide was converted into a gene transfer peptide that binds to DNA and polymerized through disulfide bond formation. Melittin analogues were synthesized by addition of one to four Lys repeats at either the C or N-subterminal end along with terminal Cys residues. Melittin analogues were able to bind and polymerize on plasmids resulting in the formation of DNA condensates. In the absence of DNA, melittin analogues retained their red blood cell hemolytic po...
Neuroprotective peptides related to Alzheimer's disease
Czech Academy of Sciences Publication Activity Database
Slaninová, Jiřina; Borovičková, Lenka; Bláha, I.; Hlaváček, Jan; Krejčová, G.; Patočka, J.
Patras : Typorama, 2005 - (Cordopatis, P.; Manessi-Zoupa, E.; Pairas, G.), 147-154 ISBN 960-7620-31-3. [Hellenic Forum on Bioactive Peptides /4./. Patras (GR), 22.04.2004-24.04.2004] R&D Projects: GA ČR(CZ) GA305/03/1100 Institutional research plan: CEZ:AV0Z40550506 Keywords : peptides * Alzheimer's disease * humanin Subject RIV: CE - Biochemistry
Bioactive peptides and proteins in disease
Refai, Essam
Regulatory peptides and marker proteins are important to study in order to understand disease mechanisms. This applies of course also to our common diseases where all relationships are not yet known. Cancer and diabetes are two such complex diseases that affect hundreds of millions of people worldwide. This thesis addresses particular aspects of these two diseases, regarding one regulatory peptide (VIP, vasoactive intestinal polypeptide) that may be useful for tumor tracing ...
Lucifensin, a peptide behind the maggot therapy
Czech Academy of Sciences Publication Activity Database
Čeřovský, Václav
Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 22-26 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506 Keywords : lucifensin * maggot therapy * antimicrobial activity * peptide synthesis * disulfide bridge Subject RIV: CC - Organic Chemistry
Dietary fiber, gut peptides, and adipocytokines
Sánchez, David; Miguel, Marta; Aleixandre, Amaya
The consumption of dietary fiber (DF) has increased since it was related to the prevention of a range of illnesses and pathological conditions. DF can modify some gut hormones that regulate satiety and energy intake, thus also affecting lipid metabolism and energy expenditure. Among these gut hormones are ghrelin, glucagon-like peptide 1, peptide YY, and cholecystokinin. Adipose tissue is known to express and secrete a variety of products known as >adipocytokines,> which are also affected by ...
From antimicrobial to anticancer peptides. A review.
Diana eGaspar; A. Salomé eVeiga; Miguel A.R.B. eCastanho
Antimicrobial peptides (AMPs) are part of the innate immune defense mechanism of many organisms. Although AMPs have been essentially studied and developed as potential alternatives for fighting infectious diseases, their use as anticancer peptides (ACPs) in cancer therapy either alone or in combination with other conventional drugs has been regarded as a therapeutic strategy to explore. As human cancer remains a cause of high morbidity and mortality worldwide, an urgent need of new, selective...
Chemical Pyrophosphorylation of Functionally Diverse Peptides
Marmelstein, Alan M.; Yates, Lisa M.; Conway, John H.; Fiedler, Dorothea
A highly selective and convenient method for the synthesis of pyrophosphopeptides in solution is reported. The remarkable compatibility with functional groups (alcohol, thiol, amine, carboxylic acid) in the peptide substrates suggests that the intrinsic nucleophilicity of the phosphoserine residue is much higher than previously appreciated. Because the methodology operates in polar solvents, including water, a broad range of pyrophosphopeptides can be accessed. We envision these peptides will...
Tryptophan rotamer distributions in amphipathic peptides at a lipid surface.
Clayton, A H; Sawyer, W. H.
The fluorescence decay of tryptophan is a sensitive indicator of its local environment within a peptide or protein. We describe the use of frequency domain fluorescence spectroscopy to determine the conformational and environmental changes associated with the interaction of single tryptophan amphipathic peptides with a phospholipid surface. The five 18-residue peptides studied are based on a class A amphipathic peptide known to associate with lipid bilayers. The peptides contain a single tryp...
Stereo-separations of Peptides by Capillary Electrophoresis and Chromatography
Authors: Afzal Hussain, Iqbal Hussain, Mohamed F. Al-Ajmi & Imran Ali ### Abstract Small peptides (di-, tri-, tetra- penta- hexa etc. and peptides) control many chemical and biological processes. The biological importance of stereomers of peptides is of great value. The stereo-separations of peptides are gaining importance in biological and medicinal sciences and pharmaceutical industries. There is a great need of experimental protocols of stereo-separations of peptides. The vario...
Constructing bioactive peptides with pH-dependent activities
Tu, Zhigang; Volk, Melanie; Shah, Khushali; Clerkin, Kevin; Liang, Jun F.
Many bioactive peptides are featured by their arginine and lysine rich contents. In this study, lysine and arginine residues in lytic peptides were selectively replaced by histidines. Although resulted histidine-containing lytic peptides had decreased activity, they did show pH-dependent cytotoxicity. The activity of the constructed histidine-containing lytic peptides increased 2 ~ 8 times as the solution pH changed from of 7.4 to 5.5. More importantly, these histidine-containing peptides mai...
Design, synthesis and analysis of novel SMAC-based peptides
Czech Academy of Sciences Publication Activity Database
Georgieva, M.; Dzimbova, T.; Sázelová, Petra; Detcheva, R.; Kašička, Václav; Pajpanova, T.
Sofia: Bulgarian Peptide Society, 2015 - (Naydenova, E.; Pajpanova, T.; Danalev, D.), s. 178-179 ISBN 978-619-90427-2-4. [Peptides 2014. European Peptide Symposium /33./. Sofia (BG), 31.08.2014-05.09.2014] Institutional support: RVO:61388963 Keywords : peptides * analysis * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation http://bulpepsoc.info/wp-content/uploads/2015/06/PEPTIDES-2014-electronic-version.pdf
Membrane manufacture for peptide separations
Kim, DooLi
Nanostructured polymeric membranes are key tools in biomedical applications such as hemodialysis, protein separations, in the food industry, and drinking water supply from seawater. Despite of the success in different separation processes, membrane manufacture itself is at risk, since the most used solvents are about to be banned in many countries due to environmental and health issues. We propose for the first time the preparation of polyethersulfone membranes based on dissolution in the ionic liquid 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DEP). We obtained a series of membranes tailored for separation of solutes with molecular weight of 30, 5, 1.3, and 1.25 kg mol-1 with respective water permeances of 140, 65, 30 and 20 Lm-2h-1bar-1. We demonstrate their superior efficiency in the separation of complex mixtures of peptides with molecular weights in the range of 800 to 3500 gmol-1. Furthermore, the thermodynamics and kinetics of phase separation leading to the pore formation in the membranes were investigated. The rheology of the solutions and the morphology of the prepared membranes were examed and compared to those of polyethersulfone in organic solvents currently used for membrane manufacture.
Relaxin family peptides and their receptors.
Bathgate, R A D; Halls, M L; van der Westhuizen, E T; Callander, G E; Kocan, M; Summers, R J
There are seven relaxin family peptides that are all structurally related to insulin. Relaxin has many roles in female and male reproduction, as a neuropeptide in the central nervous system, as a vasodilator and cardiac stimulant in the cardiovascular system, and as an antifibrotic agent. Insulin-like peptide-3 (INSL3) has clearly defined specialist roles in male and female reproduction, relaxin-3 is primarily a neuropeptide involved in stress and metabolic control, and INSL5 is widely distributed particularly in the gastrointestinal tract. Although they are structurally related to insulin, the relaxin family peptides produce their physiological effects by activating a group of four G protein-coupled receptors (GPCRs), relaxin family peptide receptors 1-4 (RXFP1-4). Relaxin and INSL3 are the cognate ligands for RXFP1 and RXFP2, respectively, that are leucine-rich repeat containing GPCRs. RXFP1 activates a wide spectrum of signaling pathways to generate second messengers that include cAMP and nitric oxide, whereas RXFP2 activates a subset of these pathways. Relaxin-3 and INSL5 are the cognate ligands for RXFP3 and RXFP4 that are closely related to small peptide receptors that when activated inhibit cAMP production and activate MAP kinases. Although there are still many unanswered questions regarding the mode of action of relaxin family peptides, it is clear that they have important physiological roles that could be exploited for therapeutic benefit. PMID:23303914
Confinement-dependent friction in peptide bundles.
Erbaş, Aykut; Netz, Roland R
Friction within globular proteins or between adhering macromolecules crucially determines the kinetics of protein folding, the formation, and the relaxation of self-assembled molecular systems. One fundamental question is how these friction effects depend on the local environment and in particular on the presence of water. In this model study, we use fully atomistic MD simulations with explicit water to obtain friction forces as a single polyglycine peptide chain is pulled out of a bundle of k adhering parallel polyglycine peptide chains. The whole system is periodically replicated along the peptide axes, so a stationary state at prescribed mean sliding velocity V is achieved. The aggregation number is varied between k = 2 (two peptide chains adhering to each other with plenty of water present at the adhesion sites) and k = 7 (one peptide chain pulled out from a close-packed cylindrical array of six neighboring peptide chains with no water inside the bundle). The friction coefficient per hydrogen bond, extrapolated to the viscous limit of vanishing pulling velocity V → 0, exhibits an increase by five orders of magnitude when going from k = 2 to k = 7. This dramatic confinement-induced friction enhancement we argue to be due to a combination of water depletion and increased hydrogen-bond cooperativity. PMID:23528088
Biomathematical description of synthetic peptide libraries.
Directory of Open Access Journals (Sweden)
Timo Sieber
Full Text Available Libraries of randomised peptides displayed on phages or viral particles are essential tools in a wide spectrum of applications. However, there is only limited understanding of a library's fundamental dynamics and the influences of encoding schemes and sizes on their quality. Numeric properties of libraries, such as the expected number of different peptides and the library's coverage, have long been in use as measures of a library's quality. Here, we present a graphical framework of these measures together with a library's relative efficiency to help to describe libraries in enough detail for researchers to plan new experiments in a more informed manner. In particular, these values allow us to answer-in a probabilistic fashion-the question of whether a specific library does indeed contain one of the "best" possible peptides. The framework is implemented in a web-interface based on two packages, discreteRV and peptider, to the statistical software environment R. We further provide a user-friendly web-interface called PeLiCa (Peptide Library Calculator, http://www.pelica.org, allowing scientists to plan and analyse their peptide libraries.
International Nuclear Information System (INIS)
Synthetic human C-peptide bearing a tyrosine group at its amino end is labelled with 125iodine using chloramin T or hydrogen peroxide and lactoperoxidase. The results of the two methods are compared. Antiserum to synthetic human C-peptide (without tyrosine), which was partially coupled to rabbit albumin, is raised in guinea pigs and goats. Goats show to be superior to guinea pips concerning antibody production. The so-called 'hook effect' phenomenon is observed when setting up the standard curves for the radioimmunoassay. Monotonically decreasing standard curves are obtained on dilution of antiserum with a high antibody titer which was produced by repeated immunization in goats. Free C-peptide and C-peptide bound to antiserum are separated using the anion exchange resin amberlite. Using this separation technique we excluded unspecific binding of labelled C-peptide to protein fractions in serum of diabetics. The sensitivity of our radioimmunoassay is approx. 0.3 ng C-peptide/ml serum. Intra- and interassay variability are below 10%. Human proinsulin is the only substance found to crossreact with the antiserum. (orig.)
Self-Assembly of Tetraphenylalanine Peptides.
Mayans, Enric; Ballano, Gema; Casanovas, Jordi; Díaz, Angélica; Pérez-Madrigal, Maria M; Estrany, Francesc; Puiggalí, Jordi; Cativiela, Carlos; Alemán, Carlos
Three different tetraphenylalanine (FFFF) based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies under a variety of conditions. The FFFF peptide assembles into nanotubes that show more structural imperfections at the surface than those formed by the diphenylalanine (FF) peptide under the same conditions. Periodic DFT calculations (M06L functional) were used to propose a model that consists of three FFFF molecules defining a ring through head-to-tail NH3(+)⋅⋅⋅(-)OOC interactions, which in turn stack to produce deformed channels with internal diameters between 12 and 16 Å. Depending on the experimental conditions used for the peptide incubation, N-fluorenylmethoxycarbonyl (Fmoc) protected FFFF self-assembles into a variety of polymorphs: ultra-thin nanoplates, fibrils, and star-like submicrometric aggregates. DFT calculations indicate that Fmoc-FFFF prefers a parallel rather than an antiparallel β-sheet assembly. Finally, coexisting multiple assemblies (up to three) were observed for Fmoc-FFFF-OBzl (OBzl = benzyl ester), which incorporates aromatic protecting groups at the two peptide terminals. This unusual and noticeable feature is attributed to the fact that the assemblies obtained by combining the Fmoc and OBzl groups contained in the peptide are isoenergetic. PMID:26419936
Biomathematical Description of Synthetic Peptide Libraries
Trepel, Martin
Libraries of randomised peptides displayed on phages or viral particles are essential tools in a wide spectrum of applications. However, there is only limited understanding of a library's fundamental dynamics and the influences of encoding schemes and sizes on their quality. Numeric properties of libraries, such as the expected number of different peptides and the library's coverage, have long been in use as measures of a library's quality. Here, we present a graphical framework of these measures together with a library's relative efficiency to help to describe libraries in enough detail for researchers to plan new experiments in a more informed manner. In particular, these values allow us to answer-in a probabilistic fashion-the question of whether a specific library does indeed contain one of the "best" possible peptides. The framework is implemented in a web-interface based on two packages, discreteRV and peptider, to the statistical software environment R. We further provide a user-friendly web-interface called PeLiCa (Peptide Library Calculator, http://www.pelica.org), allowing scientists to plan and analyse their peptide libraries. PMID:26042419
Neutron diffraction studies of viral fusion peptides
Bradshaw, Jeremy P.; J. M. Darkes, Malcolm; Katsaras, John; Epand, Richard M.
Membrane fusion plays a vital role in a large and diverse number of essential biological processes. Despite this fact, the precise molecular events that occur during fusion are still not known. We are currently engaged on a study of membrane fusion as mediated by viral fusion peptides. These peptides are the N-terminal regions of certain viral envelope proteins that mediate the process of fusion between the viral envelope and the membranes of the host cell during the infection process. As part of this study, we have carried out neutron diffraction measurements at the ILL, BeNSC and Chalk River, on a range of viral fusion peptides. The peptides, from simian immunodeficiency virus (SIV), influenza A and feline leukaemia virus (FeLV), were incorporated into stacked phospholipid bilayers. Some of the peptides had been specifically deuterated at key amino acids. Lamellar diffraction data were collected and analysed to yield information on the peptide conformation, location and orientation relative to the bilayer.
Peptide conversations in Gram-positive bacteria.
Monnet, Véronique; Juillard, Vincent; Gardan, Rozenn
Within Gram-positive bacteria, the expression of target genes is controlled at the population level via signaling peptides, also known as pheromones. Pheromones control a wide range of functions, including competence, virulence, and others that remain unknown. Until now, their role in bacterial gene regulation has probably been underestimated; indeed, bacteria are able to produce, by ribosomal synthesis or surface protein degradation, an extraordinary variety of peptides which are released outside bacteria and among which, some are pheromones that mediate cell-to-cell communication. The review aims at giving an updated overview of these peptide-dependant communication pathways. More specifically, it follows the whole peptide circuit from the peptide production and secretion in the extracellular medium to its interaction with sensors at bacterial surface or re-import into the bacteria where it plays its regulation role. In recent years, as we have accumulated more knowledge about these systems, it has become apparent that they are more complex than they first appeared. For this reason, more research on peptide-dependant pathways is needed to develop new strategies for controlling functions of interest in Gram-positive bacteria. In particular, such research could lead to alternatives to the use of antibiotics against pathogenic bacteria. In perspective, the review identifies new research questions that emerge in this field and that have to be addressed. PMID:25198780
III. Organometallic and Bioorganometallic Chemistry - Ferrocene Peptides
Directory of Open Access Journals (Sweden)
Kovačević, M.
Full Text Available This paper is devoted to the bioconjugates of ferrocene with naturally occuring amino acids/peptides - mostly dealing with authors' results accompanied, to a lesser degree, by the relevant literature data. Chapter 2 deals with natural peptides and peptidomimetics, mainly focusing on α-helix and β pleated sheet (as the most important elements of peptide secondary and tertiary structure, and artificial β-sheets nucleated by non-amino acid turn inducers. Chapter 3 describes peptides generated from ferrocenecarboxylic acid and ferroceneamine, as well as with the bioconjugates of heteroannulary substituted ferrocene-1,1'-dicarboxylic acid (Fcd and ferrocene-1,1'-diamine (Fcda. Chapter 4 elaborates authors' papers about peptides based on 1'-aminoferrocene-1-carboxylic acid (Fca. Chapter 5 is devoted to the new monosubstituted Fcd and Fcda conjugates with amino acids, while Chapter 6 describes our publications in the field of very topical peptidomimetics - ferrocene ureidopeptides and β peptides. Conformational analysis of the newly prepared ferrocene bioconjugates in solution and solid state was performed by means of spectroscopic methods (CD, IR, 1D- NMR, 2D-NMR, v. r. NMR, and temperature and concentration dependent NMR and DFT calculations.
Interaction of antimicrobial peptides with lipid membranes
International Nuclear Information System (INIS)
This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low temperatures that upon heating transform into a highly curved inverse hexagonal phase. Insertion of the peptide induced inverse bicontinuous cubic phases which are an ideal compromise between the curvature stress and the packing frustration. Melittin usually induced a mixture of two cubic phases, Im3m and Pn3m, with a ratio of lattice parameters close to 1.279, related to the underlying minimal surfaces. They formed during the lamellar to hexagonal phase transition and persisted during cooling till the onset of the gel phase. The phases formed at different lipid-to-peptide ratios had very similar lattice parameters. Epitaxial relationships existed between coexisting cubic phases and hexagonal or lamellar phases due to confinement of all phases to an onion vesicle, a vesicle with several layers consisting of different lipid phases. Alamethicin induced the same cubic phases, although their formation and lattice parameters were dependent on the peptide concentration. The cubic phases formed during heating from the lamellar phase and their onset
Interaction of antimicrobial peptides with lipid membranes
Energy Technology Data Exchange (ETDEWEB)
Hanulova, Maria
This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low temperatures that upon heating transform into a highly curved inverse hexagonal phase. Insertion of the peptide induced inverse bicontinuous cubic phases which are an ideal compromise between the curvature stress and the packing frustration. Melittin usually induced a mixture of two cubic phases, Im3m and Pn3m, with a ratio of lattice parameters close to 1.279, related to the underlying minimal surfaces. They formed during the lamellar to hexagonal phase transition and persisted during cooling till the onset of the gel phase. The phases formed at different lipid-to-peptide ratios had very similar lattice parameters. Epitaxial relationships existed between coexisting cubic phases and hexagonal or lamellar phases due to confinement of all phases to an onion vesicle, a vesicle with several layers consisting of different lipid phases. Alamethicin induced the same cubic phases, although their formation and lattice parameters were dependent on the peptide concentration. The cubic phases formed during heating from the lamellar phase and their onset
Peptide-membrane interactions of arginine-tryptophan peptides probed using quartz crystal microbalance with dissipation monitoring.
Rydberg, Hanna A
Membrane-active peptides include peptides that can cross cellular membranes and deliver macromolecular cargo as well as peptides that inhibit bacterial growth. Some of these peptides can act as both transporters and antibacterial agents. It is desirable to combine the knowledge from these two different fields of membrane-active peptides into design of new peptides with tailored actions, as transporters of cargo or as antibacterial substances, targeting specific membranes. We have previously shown that the position of the amino acid tryptophan in the peptide sequence of three arginine-tryptophan peptides affects their uptake and intracellular localization in live mammalian cells, as well as their ability to inhibit bacterial growth. Here, we use quartz crystal microbalance with dissipation monitoring to assess the induced changes caused by binding of the three peptides to supported model membranes composed of POPC, POPC/POPG, POPC/POPG/cholesterol or POPC/lactosyl PE. Our results indicate that the tryptophan position in the peptide sequence affects the way these peptides interact with the different model membranes and that the presence of cholesterol in particular seems to affect the membrane interaction of the peptide with an even distribution of tryptophans in the peptide sequence. These results give mechanistic insight into the function of these peptides and may aid in the design of membrane-active peptides with specified cellular targets and actions.
Urodilatin. A renal natriuretic peptide
International Nuclear Information System (INIS)
Development and validation of a radioimmunoassay for endogenous URO in urine and synthetic URO in plasma is described. The first obstacle to overcome was to produce an antibody specific for URO. A polyclonal URO antibody with a cross-reactivity with the structural highly homologous atrial natriuretic peptide (ANP) was developed by immunization of rabbits with the whole URO(95-126). Purification of the polyclonal URO antiserum with CNBr-activated Sepharose affinity chromatography was a simple way of producing a URO-specific antibody without cross-reactivity with ANP analogues. A reliable 125I-labelled URO tracer was made with the Iodo-Gen method. Prior to the assay, the urine samples were prepared by ethanol with a recovery of unlabelled URO between 80 - 100% and the plasma samples were Sep-Pak C18 extracted with a recovery of about 50%. The radioimmunoassay is performed in 3 days, using polyethylene glycol for separation. The sensitivity of the assay was improved by sample preparation and concentration, reducing the amount of tracer and late addition, reducing the amount of antibody and increasing the incubation time and lowering the temperature of incubation. The infusion rate of 20 ng URO kg-1 min-1 was most potential and well tolerated in healthy subjects. The short-term natriuretic and diuretic effects were closely associated with a significant diminished sodium reabsorption in the distal nephron. Further studies are needed to exploit the therapeutical potential of URO, for example in patients with sodium-water retaining disorders. The therapeutical dose range will probably be narrow due to the blood pressure lowering effect of URO with infusion rates higher than 20-30 ng kg-1 min-1. (EHS)
New dendrimer - Peptide host - Guest complexes: Towards dendrimers as peptide carriers
DEFF Research Database (Denmark)
Boas, Ulrik; Sontjens, S.H.M.; Jensen, Knud Jørgen; Christensen, J.B.; Meijer, E.W.
Adamantyl urea and adamantyl thiourea modified poly(propylene imine) dendrimers act as hosts for N-terminal tert-butoxycarbonyl (Boc)-protected peptides and form chloroform-soluble complexes. investigations with NMR spectroscopy show that the peptide is bound to the dendrimer by ionic interactions...
Peptide segment ligation:A new method for synthesis of peptide and protein
Institute of Scientific and Technical Information of China (English)
@@ The protein structure-function relationships are always highlighted in the field of life science. Protein synthesis from genomic sequence data is gaining significance in the "post-genomic era" of biomedical research by providing direct access to functional proteins. The manually or automatically stepwise solid phase peptide synthesis (SPPS) allows peptide of up to 60 residues to be routinely constructed in good yield and high purity[1,2]. The assembly of longer proteins via the gene engineering technology (e.g. recombinant DNA-based molecular biology or site- directed mutagenesis) and convergent peptide synthesis are necessary. Although the current biosynthetic method allows unnatural amino acids to be incorporated into proteins or peptides[3], only ?-peptide in the protein backbone can be obtained. A lot of problems associated with the classic convergent peptide synthesis approach, such as the poor solubility, inadequate purification techniques, and limited characterization methods with the fully protected segment[6]. However, totally chemical synthetic method can easily obtain ?- or ?-peptide[4] and even branch peptide[5].
Peptide-MHC class I stability is a stronger predictor of CTL immunogenicity than peptide affinity
DEFF Research Database (Denmark)
Harndahl, Mikkel Nors; Rasmussen, Michael; Nielsen, Morten;
Peptide-MHC class I stability is a stronger predictor of CTL immunogenicity than peptide affinity Mikkel Harndahla, Michael Rasmussena, Morten Nielsenb, Soren Buusa,∗ a Laboratory of Experimental Immunology, Faculty of Health Sciences, University of Copenhagen, Denmark b Center for Biological Seq...... al., 2007. J. Immunol. 178, 7890–7901. doi:10.1016/j.molimm.2012.02.025...
Peptide biomarkers as evidence of perchlorate biodegradation.
Bansal, Reema; Crawford, Ronald L; Paszczynski, Andrzej J
Perchlorate is a known health hazard for humans, fish, and other species. Therefore, it is important to assess the response of an ecosystem exposed to perchlorate contamination. The data reported here show that a liquid chromatography-mass spectrometry-based proteomics approach for the detection of perchlorate-reducing enzymes can be used to measure the ability of microorganisms to degrade perchlorate, including determining the current perchlorate degradation status. Signature peptides derived from chlorite dismutase (CD) and perchlorate reductase can be used as biomarkers of perchlorate presence and biodegradation. Four peptides each derived from CD and perchlorate reductase subunit A (PcrA) and seven peptides derived from perchlorate reductase subunit B (PcrB) were identified as signature biomarkers for perchlorate degradation, as these sequences are conserved in the majority of the pure and mixed perchlorate-degrading microbial cultures examined. However, chlorite dismutase signature biomarker peptides from Dechloromonas agitata CKB were found to be different from those in other cultures used and should also be included with selected CD biomarkers. The combination of these peptides derived from the two enzymes represents a promising perchlorate presence/biodegradation biomarker system. The biomarker peptides were detected at perchlorate concentrations as low as 0.1 mM and at different time points both in pure cultures and within perchlorate-reducing environmental enrichment consortia. The peptide biomarkers were also detected in the simultaneous presence of perchlorate and an alternate electron acceptor, nitrate. We believe that this technique can be useful for monitoring bioremediation processes for other anthropogenic environmental contaminants with known metabolic pathways. PMID:21115710
Clinical relevance of intestinal peptide uptake
Institute of Scientific and Technical Information of China (English)
Hugh; James; Freeman
AIM: To determine available information on an independent peptide transporter 1(Pep T1) and its potential relevance to treatment, this evaluation was completed.METHODS: Fully published English language literature articles sourced through Pub Med related to protein digestion and absorption, specifically human peptide and amino acid transport, were accessed and reviewed.Papers from 1970 to the present, with particular emphasis on the past decade, were examined. In addition,abstracted information translated to English in Pub Med was also included. Finally, studies and reviews relevant to nutrient or drug uptake, particularly in human intestine were included for evaluation. This work represents a summary of all of these studies with particular reference to peptide transporter mediated assimilation of nutrients and pharmacologically active medications.RESULTS: Assimilation of dietary protein in humans involves gastric and pancreatic enzyme hydrolysis to luminal oligopeptides and free amino acids. During the ensuing intestinal phase, these hydrolytic products are transported into the epithelial cell and, eventually, the portal vein. A critical component of this process is the uptake of intact di-peptides and tri-peptides by an independent Pep T1. A number of "peptide-mimetic" pharmaceutical agents may also be transported through this carrier, important for uptake of different antibiotics, antiviral agents and angiotensin-converting enzyme inhibitors. In addition, specific peptide products of intestinal bacteria may also be transported by Pep T1, with initiation and persistence of an immune response including increased cytokine production and associated intestinal inflammatory changes. Interestingly, these inflammatory changes may also be attenuated with orallyadministered anti-inflammatory tripeptides administered as site-specific nanoparticles and taken up by this Pep T1 transport protein. CONCLUSION: Further evaluation of the role of this transporter in treatment of
A peptide & peptide nucleic acid synthesis technology for transporter molecules and theranostics--the SPPS.
Pipkorn, Ruediger; Braun, Klaus; Wiessler, Manfred; Waldeck, Waldemar; Schrenk, Hans-Hermann; Koch, Mario; Semmler, Wolfhard; Komljenovic, Dorde
Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and function of proteins is widely investigated, especially by using computer-assisted methods. Nowadays the solid phase synthesis (SPPS) chemistry emerges as a key technology and is considered as a promising methodology to design peptides for the investigation of molecular pharmacological processes at the transcriptional level. SPPS syntheses could be carried out in core facilities producing peptides for large-scale scientific implementations as presented here. PMID:24843319
A Peptide & Peptide Nucleic Acid Synthesis Technology for Transporter Molecules and Theranostics - The SPPS
Pipkorn, Ruediger; Braun, Klaus; Wiessler, Manfred; Waldeck, Waldemar; Schrenk, Hans-Hermann; Koch, Mario; Semmler, Wolfhard; Komljenovic, Dorde
Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and function of proteins is widely investigated, especially by using computer-assisted methods. Nowadays the solid phase synthesis (SPPS) chemistry emerges as a key technology and is considered as a promising methodology to design peptides for the investigation of molecular pharmacological processes at the transcriptional level. SPPS syntheses could be carried out in core facilities producing peptides for large-scale scientific implementations as presented here. PMID:24843319
Urinary Peptide Levels in Patients with Chronic Renal Failure
Directory of Open Access Journals (Sweden)
Mungli Prakash
Full Text Available Introduction: Peptide levels in urine are found to be decreased in renal failure. In the current study urinary peptide levels were determined in chronic renal failure (CRF patients. Method: 86 CRF patients and 80 healthy controls were selected for the study. Urinary proteins and peptide levels were determined by spectrophotometer based Lowry and Bradford methods. Urinary creatinine levels were determined by clinical chemistry analyzer. Results: There was significant decrease in urinary peptide levels in CRF patients and Urinary % peptides were significantly decreased in CRF patients as compared to healthy controls. Urinary % peptides correlated negatively with proteinuria. Conclusion: we have found decrease in urinary peptides and % urinary peptides in CRF patients and possibly measurement of % urinary peptides may possibly serve as better indicator in early detection of impairment in renal function.
Selection of Genetic engineering peptide ligands for TNF receptor imaging
International Nuclear Information System (INIS)
Objective: To screen the peptide ligands of TNF receptor from phage 6-mer peptide library with the purpose of developing new peptides radiopharmaceuticals for TNF receptor imaging. Methods: The soluble protein of TNF receptor I (sTNFR I) was used to screen the TNF-specific epitopes from phage 6-mer peptide library. After four rounds of affinity screening, the peptides displayed on the selected phage were directly subjected to ELISA to determine their immunological activity to sTNFR. The amino acid sequences of the peptides with highest immunological activity were deduced through DNA sequencing. And their conserved sequences were further determined. Results: Peptides sequences mimicking TNF-specific epitopes were obtained. Conclusion: The short peptides sequences mimicking TNF -specific epitopes were successfully acquired. The method which was established in the present study may provide a feasible way in peptides radiopharmaceuticals development for TNF receptor imaging. (authors)
Peptide pool immunization and CD8+ T cell reactivity
DEFF Research Database (Denmark)
Rasmussen, Susanne B; Harndahl, Mikkel N; Buus, Anette Stryhn;
peptide in the Elispot culture. Immunization with a mixture of the VSV-peptide and a "normal" peptide also resulted in IFNγ spot formation without addition of peptide to the assay culture. Peptide-tetramer staining of CD8(+) T cells from mice immunized with a mixture of VSV-peptide and "normal" peptide......Mice were immunized twice with a pool of five peptides selected among twenty 8-9-mer peptides for their ability to form stable complexes at 37°C with recombinant H-2K(b) (half-lives 10-15h). Vaccine-induced immunity of splenic CD8(+) T cells was studied in a 24h IFNγ Elispot assay. Surprisingly...... peptides induced normal peptide immunity i.e. the specific T cell reactivity in the Elispot culture was strictly dependent on exposure to the immunizing peptide ex vivo. However, immunization with two of the peptides, a VSV- and a Mycobacterium-derived peptide, resulted in IFNγ spot formation without...
Peptide inhibition of human cytomegalovirus infection
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Morris Cindy A
Full Text Available Abstract Background Human cytomegalovirus (HCMV is the most prevalent congenital viral infection in the United States and Europe causing significant morbidity and mortality to both mother and child. HCMV is also an opportunistic pathogen in immunocompromised individuals, including human immunodeficiency virus (HIV- infected patients with AIDS, and solid organ and allogeneic stem cell transplantation recipients. Current treatments for HCMV-associated diseases are insufficient due to the emergence of drug-induced resistance and cytotoxicity, necessitating novel approaches to limit HCMV infection. The aim of this study was to develop therapeutic peptides targeting glycoprotein B (gB, a major glycoprotein of HCMV that is highly conserved across the Herpesviridae family, that specifically inhibit fusion of the viral envelope with the host cell membrane preventing HCMV entry and infection. Results Using the Wimley-White Interfacial Hydrophobicity Scale (WWIHS, several regions within gB were identified that display a high potential to interact with lipid bilayers of cell membranes and hydrophobic surfaces within proteins. The ability of synthetic peptides analogous to WWIHS-positive sequences of HCMV gB to inhibit viral infectivity was evaluated. Human foreskin fibroblasts (HFF were infected with the Towne-GFP strain of HCMV (0.5 MOI, preincubated with peptides at a range of concentrations (78 nm to 100 μM, and GFP-positive cells were visualized 48 hours post-infection by fluorescence microscopy and analyzed quantitatively by flow cytometry. Peptides that inhibited HCMV infection demonstrated different inhibitory concentration curves indicating that each peptide possesses distinct biophysical properties. Peptide 174-200 showed 80% inhibition of viral infection at a concentration of 100 μM, and 51% and 62% inhibition at concentrations of 5 μM and 2.5 μM, respectively. Peptide 233-263 inhibited infection by 97% and 92% at concentrations of 100 �
The Equilibrium Thermodynamics of Various Peptide Sequences
Yaşar, Fatih
The equilibrium thermodynamic properties of two peptide sequences of β-casein in the α-helix regions were studied by three-dimensional molecular modeling in vacuum. All the three-dimensional conformations of each peptide sequences were obtained by multicanonical simulations using ECEPP/2 force field and each simulation was started from completely random initial conformation. No a-priori information about ground-state is used in the simulations. In the present study, we calculated the average values of total energy, specific heat, fourth-order cumulant for two peptide sequences of β-casein as a function of temperature. We observed that the specific heat shows two peaks as a function of temperature for both peptides. Because our sequences have highly helical structure and two peaks in the specific heat, we have also studied the helix-coil transitions to determine these peaks. Our data indeed show these peptides have highly helical structure and better agreement with the results of spectroscopic techniques and other prediction methods.
Biosynthetic engineering of nonribosomal peptide synthetases.
Kries, Hajo
From the evolutionary melting pot of natural product synthetase genes, microorganisms elicit antibiotics, communication tools, and iron scavengers. Chemical biologists manipulate these genes to recreate similarly diverse and potent biological activities not on evolutionary time scales but within months. Enzyme engineering has progressed considerably in recent years and offers new screening, modelling, and design tools for natural product designers. Here, recent advances in enzyme engineering and their application to nonribosomal peptide synthetases are reviewed. Among the nonribosomal peptides that have been subjected to biosynthetic engineering are the antibiotics daptomycin, calcium-dependent antibiotic, and gramicidin S. With these peptides, incorporation of unnatural building blocks and modulation of bioactivities via various structural modifications have been successfully demonstrated. Natural product engineering on the biosynthetic level is not a reliable method yet. However, progress in the understanding and manipulation of biosynthetic pathways may enable the routine production of optimized peptide drugs in the near future. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:27465074
Glucagon-Like Peptide-1 Gene Therapy
Directory of Open Access Journals (Sweden)
Anne M. Rowzee
Full Text Available Glucagon-like peptide 1 (GLP-1 is a small peptide component of the prohormone, proglucagon, that is produced in the gut. Exendin-4, a GLP-1 receptor agonist originally isolated from the saliva of H. suspectum or Gila monster, is a peptide that shares sequence and functional homology with GLP-1. Both peptides have been demonstrated to stimulate insulin secretion, inhibit glucagon secretion, promote satiety and slow gastric emptying. As such, GLP-1 and Exendin-4 have become attractive pharmaceutical targets as an adjunctive therapy for individuals with type II diabetes mellitus, with several products currently available clinically. Herein we summarize the cell biology leading to GLP-1 production and secretion from intestinal L-cells and the endocrine functions of this peptide and Exendin-4 in humans. Additionally, gene therapeutic applications of GLP-1 and Exendin-4 are discussed with a focus on recent work using the salivary gland as a gene therapy target organ for the treatment of diabetes mellitus.
Peptide friction in water nanofilm on mica surface
Institute of Scientific and Technical Information of China (English)
Zhou Bo; Xiu Peng; Wang Chun-Lei; Fang Hai-Ping
Peptide frictions in water nanofilms of various thicknesses on a mica surface are studied via molecular dynamics simulations.We find that the forced lateral motion of the peptide exhibits stick-slip behaviour at low water coverage;in contrast,the smooth gliding motion is observed at higher water coverage.The adsorbed peptide can form direct peptide-surface hydrogen bonds as well as indirect peptide-water-surface hydrogen bonds with the substrate. We propose that the stick-slip phenomenon is attributed to the overall effects of direct and indirect hydrogen bonds formed between the surface and the peptide.
Insulin and C-peptide in human brain neurons (insulin/C-peptide/brain peptides/immunohistochemistry/radioimmunoassay)
International Nuclear Information System (INIS)
The regional distribution and cellular localization of insulin and C-peptide immunoreactivities were studied in human cadaver brains using the indirect immunofluorescence method, the peroxidase-antiperoxidase technique, and radioimmunoassay. Products of the immune reactions to both polypeptides were observed in most nerve cells in all areas of the brain examined. Immunostaining was mainly restricted to the cell soma and proximal dendrites. Radioimmunoassay revealed that human brain contains insulin and C-peptide in concentrations much higher than the blood, the highest being in the hypothalamus. These findings support the hypothesis that the 'brain insulin' is - at least in part - produced in the CNS. (author)
Anisotropic membrane curvature sensing by antibacterial peptides
Gómez-Llobregat, Jordi; Lindén, Martin
Many proteins and peptides have an intrinsic capacity to sense and induce membrane curvature, and play crucial roles for organizing and remodeling cell membranes. However, the molecular driving forces behind these processes are not well understood. Here, we describe a new approach to study curvature sensing, by simulating the direction-dependent interactions of single molecules with a buckled lipid bilayer. We analyze three antimicrobial peptides, a class of membrane-associated molecules that specifically target and destabilize bacterial membranes, and find qualitatively different sensing characteristics that would be difficult to resolve with other methods. These findings provide new insights into the microscopic mechanisms of antimicrobial peptides, which might aid the development of new antibiotics. Our approach is generally applicable to a wide range of curvature sensing molecules, and our results provide strong motivation to develop new experimental methods to track position and orientation of membrane p...
Anisotropic Membrane Curvature Sensing by Amphipathic Peptides.
Gómez-Llobregat, Jordi; Elías-Wolff, Federico; Lindén, Martin
Many proteins and peptides have an intrinsic capacity to sense and induce membrane curvature, and play crucial roles for organizing and remodeling cell membranes. However, the molecular driving forces behind these processes are not well understood. Here, we describe an approach to study curvature sensing by simulating the interactions of single molecules with a buckled lipid bilayer. We analyze three amphipathic antimicrobial peptides, a class of membrane-associated molecules that specifically target and destabilize bacterial membranes, and find qualitatively different sensing characteristics that would be difficult to resolve with other methods. Our findings provide evidence for direction-dependent curvature sensing mechanisms in amphipathic peptides and challenge existing theories of hydrophobic insertion. The buckling approach is generally applicable to a wide range of curvature-sensing molecules, and our results provide strong motivation to develop new experimental methods to track position and orientation of membrane proteins. PMID:26745422
Antimicrobial peptides in innate immune responses
DEFF Research Database (Denmark)
Sorensen, O.E.; Borregaard, N.; Cole, A.M.
novo synthesis or by proteolytic cleavage from antimicrobially inactive proproteins. Studies of human diseases and animal studies have given important clues to the in vivo role of AMPs. It is now evident that dysregulation of the generation of AMPs in innate immune responses plays a role in certain......Antimicrobial peptides (AMPs) are ancient effector molecules in the innate immune response of eukaryotes. These peptides are important for the antimicrobial efficacy of phagocytes and for the innate immune response mounted by epithelia of humans and other mammals. AMPs are generated either by de...... diseases like Crohn's disease and atopic dermatitis. AMPs are attractive candidates for development of novel antibiotics due to their in vivo activity profile and some peptides may serve as templates for further drug development Udgivelsesdato: 2008...
Peptide Based Radiopharmaceuticals: Specific Construct Approach
Energy Technology Data Exchange (ETDEWEB)
Som, P; Rhodes, B A; Sharma, S S
The objective of this project was to develop receptor based peptides for diagnostic imaging and therapy. A series of peptides related to cell adhesion molecules (CAM) and immune regulation were designed for radiolabeling with 99mTc and evaluated in animal models as potential diagnostic imaging agents for various disease conditions such as thrombus (clot), acute kidney failure, and inflection/inflammation imaging. The peptides for this project were designed by the industrial partner, Palatin Technologies, (formerly Rhomed, Inc.) using various peptide design approaches including a newly developed rational computer assisted drug design (CADD) approach termed MIDAS (Metal ion Induced Distinctive Array of Structures). In this approach, the biological function domain and the 99mTc complexing domain are fused together so that structurally these domains are indistinguishable. This approach allows construction of conformationally rigid metallo-peptide molecules (similar to cyclic peptides) that are metabolically stable in-vivo. All the newly designed peptides were screened in various in vitro receptor binding and functional assays to identify a lead compound. The lead compounds were formulated in a one-step 99mTc labeling kit form which were studied by BNL for detailed in-vivo imaging using various animals models of human disease. Two main peptides usingMIDAS approach evolved and were investigated: RGD peptide for acute renal failure and an immunomodulatory peptide derived from tuftsin (RMT-1) for infection/inflammation imaging. Various RGD based metallopeptides were designed, synthesized and assayed for their efficacy in inhibiting ADP-induced human platelet aggregation. Most of these peptides displayed biological activity in the 1-100 µM range. Based on previous work by others, RGD-I and RGD-II were evaluated in animal models of acute renal failure. These earlier studies showed that after acute ischemic injury the renal cortex displays
Metal Ion Controlled Polymorphism of a Peptide
DEFF Research Database (Denmark)
Hemmingsen, Lars Bo Stegeager; Jancso, Attila; Szunyogh, Daniel; Larsen, Flemming Hofmann; Thulstrup, Peter Waaben; Christensen, Niels Johan; Gyurcsik, Bela
In this work a metal ion binding model dodecapeptide was investigated in terms of its capacity to adopt different structures depending on the metal ion to peptide stoichiometry. The dodecapeptide is much simpler than real proteins, yet displays sufficient complexity to model the effect of metal...... ions on fully or partially unstructured proteins, or the effect of metal ions on protein aggregation. Metal ions may be employed to fold (or misfold) individual peptides in a controlled manner depending on the potential metal ion coordinating amino acid side chains (Cys, His, Asp, Glu, …) in the...... peptide, and the ligand and structural preferences of the metal ion (in our studies Zn2+, Cd2+, Hg2+, Cu+/2+). Simultaneously, new species such as metal ion bridged ternary complexes or even oligomers may be formed. In recent previous studies we have observed similar polymorphism of zinc finger model...
Peptides as catalysts in the RNA world
DEFF Research Database (Denmark)
Wieczorek, Rafal; Dörr, Mark; Luisi, Pier Luigi;
the RNA world concept. Contrary to RNA building blocks, amino acids form quite easily in simulated prebiotic reactions. Also, many prebiotic scenarios for condensation of amino acids into peptides have been proposed and successfully demonstrated experimentally (Rode 1999). We also have growing body of...... experimental evidence showing various catalytic activities associated with short chain peptides, some of them as small as dipeptides. One such peptide, composed of only two amino acid residues; serine and histidine, was reported to exhibit broad hydrolytic activities. The dipeptide SerHis can catalyze the...... hydrolysis of esters, proteins and nucleic acids (Li et al. 2000). The direction of the catalysis either toward hydrolysis or condensation is determined by thermodynamic constraints. In an aqueous medium (a general requirement for prebiotically compatible reactions), hydrolysis is thermodynamically favored...
Design and Application of Antimicrobial Peptide Conjugates.
Reinhardt, Andre; Neundorf, Ines
Antimicrobial peptides (AMPs) are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT) or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry. PMID:27187357
Silica precipitation with synthetic silaffin peptides.
Wieneke, Ralph; Bernecker, Anja; Riedel, Radostan; Sumper, Manfred; Steinem, Claudia; Geyer, Armin
Silaffins are highly charged proteins which are one of the major contributing compounds that are thought to be responsible for the formation of the hierarchically structured silica-based cell walls of diatoms. Here we describe the synthesis of an oligo-propyleneamine substituted lysine derivative and its incorporation into the KXXK peptide motif occurring repeatedly in silaffins. N(ε)-alkylation of lysine was achieved by a Mitsunobu reaction to obtain a protected lysine derivative which is convenient for solid phase peptide synthesis. Quantitative silica precipitation experiments together with structural information about the precipitated silica structures gained by scanning electron microscopy revealed a dependence of the amount and form of the silica precipitates on the peptide structure. PMID:21674108
Design and Application of Antimicrobial Peptide Conjugates
Directory of Open Access Journals (Sweden)
Andre Reinhardt
Full Text Available Antimicrobial peptides (AMPs are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry.
Diagnostic and immunoprophylactic applications of synthetic peptides in veterinary microbiology
Directory of Open Access Journals (Sweden)
Saravanan Paramasivam
Full Text Available Chemically synthesized peptides are considered as potential reagents for various applications in biological sciences. They mimic naturally occurring peptides or segments of proteins and have emerged as diagnostic reagents and safe immunogens in animal science. Carefully selected peptides resembling authentic epitopes serve as synthetic antigens in diagnostic tests. Synthetic peptide-based vaccines can elicit antibodies against animal pathogens. The early use of synthetic peptides as a vaccine for foot-and-mouth disease stimulated interest in the development of peptide-based diagnostics and immunoprophylactics. The development of a peptide vaccine for canine parvovirus confirmed the usefulness of peptides as immunoprophylactics. Recently, the advent of the technology for the development of multiple antigenic peptides (MAPs has provided a well-defined method for the production of highly immunogenic peptides and anti-peptide antibodies. Antibodies raised against major epitopes can be used in the detection of the native antigen (virus in the enzyme-linked immunosorbent assay (ELISA and other tests, vindicating the usefulness of peptides for safe, chemically defined, non-infectious diagnostics and immunoprophylactics. This article focuses on the methods for selecting and preparing peptides for the predicted epitopes, their characterization and use, and the application of MAPs.
Interactions at the Peptide/Silicon Surfaces: Evidence of Peptide Multilayer Assembly.
Pápa, Zsuzsanna; Ramakrishnan, Sathish Kumar; Martin, Marta; Cloitre, Thierry; Zimányi, László; Márquez, Jessica; Budai, Judit; Tóth, Zsolt; Gergely, Csilla
Selective deposition of peptides from liquid solutions to n- and p-doped silicon has been demonstrated. The selectivity is governed by peptide/silicon adhesion differences. A noninvasive, fast characterization of the obtained peptide layers is required to promote their application for interfacing silicon-based devices with biological material. In this study we show that spectroscopic ellipsometry-a method increasingly used for the investigation of biointerfaces-can provide essential information about the amount of adsorbed peptide material and the degree of coverage on silicon surfaces. We observed the formation of peptide multilayers for a strongly binding adhesion peptide on p-doped silicon. Application of the patterned layer ellipsometric evaluation method combined with Sellmeier dispersion led to physically consistent results, which describe well the optical properties of peptide layers in the visible spectral range. This evaluation allowed the estimation of surface coverage, which is an important indicator of adsorption quality. The ellipsometric findings were well supported by atomic force microscopy results. PMID:27315212
Aerosolized Medications for Gene and Peptide Therapy.
Laube, Beth L
Inhalation therapy has matured to include drugs that: (1) deliver nucleic acids that either lead to the restoration of a gene construct or protein coding sequence in a population of cells or suppress or disrupt production of an abnormal gene product (gene therapy); (2) deliver peptides that target lung diseases such as asthma, sarcoidosis, pulmonary hypertension, and cystic fibrosis; and (3) deliver peptides to treat diseases outside the lung whose target is the systemic circulation (systemic drug delivery). These newer applications for aerosol therapy are the focus of this paper, and I discuss the status of each and the challenges that remain to their successful development. Drugs that are highlighted include: small interfering ribonucleic acid to treat lung cancer and Mycobacterium tuberculosis; vectors carrying the normal alpha-1 antitrypsin gene to treat alpha-1 antitrypsin deficiency; vectors carrying the normal cystic fibrosis transmembrane conductance regulator gene to treat cystic fibrosis; vasoactive intestinal peptide to treat asthma, pulmonary hypertension, and sarcoidosis; glutathione to treat cystic fibrosis; granulocyte-macrophage colony-stimulating factor to treat pulmonary alveolar proteinosis; calcitonin for postmenopausal osteoporosis; and insulin to treat diabetes. The success of these new aerosol applications will depend on many factors, such as: (1) developing gene therapy formulations that are safe for acute and chronic administrations to the lung, (2) improving the delivery of the genetic material beyond the airway mucus barrier and cell membrane and transferring the material to the cell cytoplasm or the cell nucleus, (3) developing aerosol devices that efficiently deliver genetic material and peptides to their lung targets over a short period of time, (4) developing devices that increase aerosol delivery to the lungs of infants, (5) optimizing the bioavailability of systemically delivered peptides, and (6) developing peptide formulations for
Selection of trkB-binding peptides from a phage-displayed random peptide library
Institute of Scientific and Technical Information of China (English)
马仲才; 吴晓兰; 曹明媚; 潘卫; 朱分禄; 陈景山; 戚中田
Brain-derived neurotrophic factor (BDNF) shows potential in the treatment of neurodegenerative diseases, but the therapeutic application of BDNF has been greatly limited because it is too large in molecular size to permeate blood-brain barrier. To develop low-molecular-weight BDNF-like peptides, we selected a phage-displayed random peptide library using trkB expressed on NIH 3T3 cells as target in the study. With the strategy of peptide library incubation with NIH 3T3 cells and competitive elution with 1 υg/mL of BDNF in the last round of selection, the specific phages able to bind to the natural conformation of trkB and antagonize BDNF binding to trkB were enriched effectively. Five trkB-binding peptides were obtained, in which a core sequence of CRA/TXφXXφXXC (X represents the random amino acids, φ represents T, L or I) was identified. The BDNF-like activity of these five peptides displayed on phages was not observed, though all of them antagonized the activity of BDNF in a dose-dependent manner. Similar results were obtained with the synthetic peptide of C1 clone, indicating that the 5 phage-derived peptides were trkB antagonists. These low-molecular-weight antagonists of trkB may be of potential application in the treatment of neuroblastoma and chronic pain. Meanwhile, the obtained core sequence also could be used as the base to construct the secondary phage-displayed peptide library for further development of small peptides mimicking BDNF activity.
A cyclic peptidic serine protease inhibitor
DEFF Research Database (Denmark)
Zhao, Baoyu; Xu, Peng; Jiang, Longguang;
pocket, its carbonyl group aligning improperly relative to Ser195 and the oxyanion hole, explaining why the peptide is an inhibitor rather than a substrate. Substitution of the P1 Arg with novel unnatural Arg analogues with aliphatic or aromatic ring structures led to an increased affinity, depending on......, in spite of a less favorable binding entropy and loss of a polar interaction. We conclude that increased flexibility of the peptide allows more favorable exosite interactions, which, in combination with the use of novel Arg analogues as P1 residues, can be used to manipulate the affinity and...
Radioimmunoassay for C-peptide and proinsulin
International Nuclear Information System (INIS)
Proinsulin, the biosynthetic precursor of insulin, was discovered by Steiner et al. (1967) and shown to be converted to insulin and C-peptide in the β-cell. The first part of this paper deals with aspects of the radioimmunoassay for C-peptide with special emphasis on the development and the sources of errors encountered in our laboratory (Heding, 1975; Naithani et al., 1975). The second part deals with the many problems involved in the determination of human proinsulin and describes a direct and specific radioimmunoassay developed for measuring proinsulin in serum with a detection limit of less than 0.01 pmol/ml. (Auth.)
Minimizing acylation of peptides in PLGA microspheres
Zhang, Ying; Schwendeman, Steven P.
The main objective of this study was to characterize and find mechanisms to prevent acylation of therapeutic peptides encapsulated in glucose-star poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres. The effect of addition of divalent cation salts CaCl2, MnCl2 as well as carboxymethyl chitosan (CMCS) on inhibition of acylation of octreotide (Oct), salmon calcitonin (sCT), and human parathyroid hormone (hPTH) was evaluated. Peptide content and integrity inside the degrading microspheres was ...
Novel endogenous peptide agonists of cannabinoid receptors
Gomes, Ivone; Grushko, Julia S.; Golebiewska, Urszula; Hoogendoorn, Sascha; Gupta, Achla; Heimann, Andrea S.; Ferro, Emer S.; Scarlata, Suzanne; Fricker, Lloyd D.; Devi, Lakshmi A.
Hemopressin (Hp), a 9-residue α-hemoglobin-derived peptide, was previously reported to function as a CB1 cannabinoid receptor antagonist (1). In this study, we report that mass spectrometry (MS) data from peptidomics analyses of mouse brain extracts identified N-terminally extended forms of Hp containing either three (RVD-Hpα) or two (VD-Hpα) additional amino acids, as well as a β-hemoglobin-derived peptide with sequence similarity to that of hemopressin (VD-Hpβ). Characterization of the α-he...
Activity of Cathelicidin Peptides against Simkania negevensis
Directory of Open Access Journals (Sweden)
Manuela Donati
Full Text Available The in vitro activity of six cathelicidin peptides against the reference strain Z of Simkania negevensis was investigated. Five peptides—PG-1, Bac7, SMAP-29, BMAP-27, and BMAP-28—proved to be active at very low concentrations (1 to 0.1 μg/mL, while LL-37 cathelicidin was ineffective even at a concentration of 100 μg/mL. In comparison to chlamydiae, S. negevensis proved to be more susceptible to the antimicrobial peptides tested.
Analysis of antimicrobial peptides by capillary electrophoresis
Czech Academy of Sciences Publication Activity Database
Ehala, Sille; Niederhafner, Petr; Čeřovský, Václav; Řezanka, P.; Sýkora, D.; Král, V.; Kašička, Václav
Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 37-40 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] R&D Projects: GA ČR(CZ) GA203/09/0675; GA ČR(CZ) GA203/08/1428 Institutional research plan: CEZ:AV0Z40550506 Keywords : capillary electrophoresis * antimicrobial peptides * gold nanoparticles Subject RIV: CC - Organic Chemistry
[Antimicrobial peptide in dentisty. Literature review].
Sato, F Simain; Rompen, E; Heinen, E
The use of antimicrobial substances has contributed to the development of multiple antimicrobial resistances (1), challenging the pharmaceutical industry to develop with new, innovative, and effective molecules. Discovered around 1980, molecules called natural antimicrobial peptides (AMPs) appear to hold great potential for the treatment of infections. These cationic peptides are able to stop the bacterial development and to control infections. The purpose of this review is to help improve the understanding of the way AMPs operate in the context of the development of new cures against viruses, bacteria, and mushrooms found in the human body in general and in the oral cavity in particular. PMID:20143750
Radiometallating antibodies and biologically active peptides
International Nuclear Information System (INIS)
We have developed methods to radiolabel large molecules, using porphyrins as bifunctional chelating agents for radiometals. The porphyrins are substituted with an N-benzyl group to activate them for radiometallation under mild reaction conditions. Porphyrins that have on functional group for covalent attachment to other molecules cannot cause crosslinking. We have examined the labeling chemistry for antibodies, and we have also developed methods to label smaller biologically active molecules, such as autoantigenic peptides. The autoantigenic peptides, fragments of the acetylcholine receptor, are under investigation for myasthenia gravis research. The methods of covalent attachment of these bifunctional chelating agents to large molecules and the radiometallation chemistry will be discussed
A Candida albicans PeptideAtlas
Vialas, Vital; Sun, Zhi; Loureiro y Penha, Carla Verónica; Carrascal, Montserrat; Abián, Joaquín; Monteoliva, Lucía; Deutsch, Eric W.; Aebersold, Ruedi; Moritz, Robert L.; Gil, Concha
Candida albicans public proteomic datasets, though growing steadily in the last few years, still have a very limited presence in online repositories. We report here the creation of a C. albicans PeptideAtlas comprising near 22,000 distinct peptides at a 0.24% False Discovery Rate (FDR) that account for over 2500 canonical proteins at a 1.2% FDR. Based on data from 16 experiments, we attained coverage of 41% of the C. albicans open reading frame sequences (ORFs) in the database used for the se...
Peptoid-Peptide hybrid backbone architectures
DEFF Research Database (Denmark)
Olsen, Christian Adam
Peptidomimetic oligomers and foldamers have received considerable attention for over a decade, with beta-peptides and the so-called peptoids (N-alkylglycine oligomers) representing prominent examples of such architectures. Lately, hybrid or mixed backbones consisting of both alpha- and beta......-amino acids (alpha/beta-peptides) have been investigated in some detail as well. The present Minireview is a survey of the literature concerning hybrid structures of alpha-amino acids and peptoids, including beta-peptoids (N-alkyl-beta-alanine oligomers), and is intended to give an overview of this area...
Stable Peptides Instead of Stapled Peptides: Highly Potent αvβ6-Selective Integrin Ligands.
Maltsev, Oleg V; Marelli, Udaya Kiran; Kapp, Tobias G; Di Leva, Francesco Saverio; Di Maro, Salvatore; Nieberler, Markus; Reuning, Ute; Schwaiger, Markus; Novellino, Ettore; Marinelli, Luciana; Kessler, Horst
The αvβ6 integrin binds the RGD-containing peptide of the foot and mouth disease virus with high selectivity. In this study, the long binding helix of this ligand was downsized to an enzymatically stable cyclic peptide endowed with sub-nanomolar binding affinity toward the αvβ6 receptor and remarkable selectivity against other integrins. Computational studies were performed to disclose the molecular bases underlying the high binding affinity and receptor subtype selectivity of this peptide. Finally, the utility of the ligand for use in biomedical studies was also demonstrated here. PMID:26663660
Calcitonin gene-related peptide (CGRP), peptide YY (PYY) gastrin releasing peptide (GRP) and others in hamster lung and plasma
International Nuclear Information System (INIS)
Rabbit antisera to CGRP, PYY, neuropeptide Y (NPY) and GRP were used for immunocytochemical localization of these peptides in lungs of neonate hamsters at birth and 6 d of age and young (70 gm) and adult (107 gm) hamsters. The peroxidase-antiperoxidase method was applied to paraffin sections of tissue fixed in Bouin's or Zamboni's solution. Furthermore, radioimmunoassay (RIA) was used to quantify these peptides in lung tissue and plasma from the young hamsters (n=13). Distinct CGRP-like immunoreactivity (IR) was noted in grouped (NEB) and individual (NEC) neuroendocrine cells at all ages including all airways from trachea (NECs only) to alveoli. In some NEBs this IR coexisted with 5-HT-like IR. PYY- and NPY-like Ir was mainly noted in NEBs and NECs at the level of bronchioles and alveoli, and weak GRP-like IR was present in neuroendocrine-like cells of small airways. Measurable quantities of all peptides were recorded by RIA. Females had higher lung and plasma levels of CGRP and plasma levels of PYY than males and tended to have higher lung levels of GRP. The neuropeptides CGRP, PYY and the analog NPY are putative regulators of local pulmonary blood flow by vasodilation (CGRP) and constriction (PYY, NPY), and GRP is known to regulate peptide release
Helical synthetic peptides that stimulate cellular cholesterol efflux
Bielicki, John K.; Natarajan, Pradeep
The present invention provides peptides comprising at least one amphipathic alpha helix and having an cholesterol mediating activity and a ABCA stabilization activity. The invention further provides methods of using such peptides.
B-type natriuretic peptide secretion following scuba diving
DEFF Research Database (Denmark)
Passino, Claudio; Franzino, Enrico; Giannoni, Alberto;
To examine the neurohormonal effects of a scuba dive, focusing on the acute changes in the plasma concentrations of the different peptide fragments from the B-type natriuretic peptide (BNP) precursor.......To examine the neurohormonal effects of a scuba dive, focusing on the acute changes in the plasma concentrations of the different peptide fragments from the B-type natriuretic peptide (BNP) precursor....
Highly flexible protein-peptide docking using CABS-dock
Ciemny, Maciej Pawel; Kurcinski, Mateusz; Kozak, Konrad Jakub; Kolinski, Andrzej; Kmiecik, Sebastian
Protein-peptide molecular docking is a difficult modeling problem. It is even more challenging when significant conformational changes that may occur during the binding process need to be predicted. In this chapter, we demonstrate the capabilities and features of the CABS-dock server for flexible protein-peptide docking. CABS-dock allows highly efficient modeling of full peptide flexibility and significant flexibility of a protein receptor. During CABS-dock docking, the peptide folding and bi...
Cancer Treatment Using Peptides: Current Therapies and Future Prospects
Jyothi Thundimadathil
This paper discusses the role of peptides in cancer therapy with special emphasis on peptide drugs which are already approved and those in clinical trials. The potential of peptides in cancer treatment is evident from a variety of different strategies that are available to address the progression of tumor growth and propagation of the disease. Use of peptides that can directly target cancer cells without affecting normal cells (targeted therapy) is evolving as an alternate strategy to convent...
Porcine parvovirus removal using trimer and biased hexamer peptides
Heldt, Caryn L.; Gurgel, Patrick V.; Jaykus, Lee-Ann; Carbonell, Ruben G.
Assuring the microbiological safety of biological therapeutics remains an important concern. Our group has recently reported small trimeric peptides that have the ability to bind and remove a model non-enveloped virus, porcine parvovirus (PPV), from complex solutions containing human blood plasma. In an effort to improve the removal efficiency of these small peptides, we created a biased library of hexamer peptides that contain two previously reported trimeric peptides designated WRW and KYY....
Post-Translational Modifications in Secreted Peptide Hormones in Plants
Matsubayashi, Yoshikatsu
More than a dozen secreted peptides are now recognized as important hormones that coordinate and specify cellular functions in plants. Recent evidence has shown that secreted peptide hormones often undergo post-translational modification and proteolytic processing, which are critical for their function. Such 'small post-translationally modified peptide hormones' constitute one of the largest groups of peptide hormones in plants. This short review highlights recent progress in research on post...
A common landscape for membrane-active peptides
Last, Nicholas B.; Schlamadinger, Diana E.; Miranker, Andrew D.
Three families of membrane-active peptides are commonly found in nature and are classified according to their initial apparent activity. Antimicrobial peptides are ancient components of the innate immune system and typically act by disruption of microbial membranes leading to cell death. Amyloid peptides contribute to the pathology of diverse diseases from Alzheimer's to type II diabetes. Preamyloid states of these peptides can act as toxins by binding to and permeabilizing cellular membranes...
Peptide Profile of Low-Fat Edam Cheese
Erdoğan KÜÇÜKÖNER
Low-fat Edam cheese was manufactured using conventional cheese-making procedures using low-fat milk (1.5% fat). The cheese samples were aged for six months at 5 to 6°C. The cheese was analyzed for biochemical characteristics and peptide content. The peptide contents were determined with reverse phase chromatography. The association property of proteins and peptides in the soluble fraction of the cheese was determined using hydrophobic interaction chromatography. The overall peptide quantit...
Microwave heating in solid-phase peptide synthesis
DEFF Research Database (Denmark)
Pedersen, Søren Ljungberg; Shelton, Anne Pernille Tofteng; Malik, Leila; Jensen, Knud Jørgen
not a panacea for all difficulties in peptide syntheses and the conditions may need to be adjusted for the incorporation of Cys, His and Asp in peptides, and for the synthesis of, for example, phosphopeptides, glycopeptides, and N-methylated peptides. Here we provide a comprehensive overview of the...
Targeting and Therapeutic Peptides in Nanomedicine for Atherosclerosis
Chung, Eun Ji
Peptides in atherosclerosis nanomedicine provide structural, targeting, and therapeutic functionality, and can assist in overcoming delivery barriers of traditional pharmaceuticals. Moreover, their inherent biocompatibility and biodegradability make them especially attractive as materials intended for use in vivo. In this review, an overview of nanoparticle-associated targeting and therapeutic peptides for atherosclerosis are provided, including peptides designed for cellular targets such as ...
Nanostructure formation enhances the activity of LPS-neutralizing peptides.
Mas-Moruno, C.; Cascales, L.; Cruz, L.J.; Mora, P.; Perez-Paya, E.; Albericio, F.
Peptides that interact with lipopolysaccharide (LPS) can provide the basis for the development of new antisepsis agents. In this work, several LPS-neutralizing acyl peptides derived from LALF, BPI, and SAP were prepared, structurally characterized, and biologically evaluated. In all cases, peptides
Cleaving Double-Stranded DNA with Peptide Nucleic Acids
DEFF Research Database (Denmark)
Peptide nucleic acids and analogues of peptide nucleic acids are used to form duplex, triplex, and other structures with nucleic acids and to modify nucleic acids. The peptide nucleic acids and analogues thereof also are used to modulate protein activity through, for example, transcription arrest...
Facilitating protein solubility by use of peptide extensions
Freimuth, Paul I; Zhang, Yian-Biao; Howitt, Jason
Expression vectors for expression of a protein or polypeptide of interest as a fusion product composed of the protein or polypeptide of interest fused at one terminus to a solubility enhancing peptide extension are provided. Sequences encoding the peptide extensions are provided. The invention further comprises antibodies which bind specifically to one or more of the solubility enhancing peptide extensions.
Practical application of natriuretic peptides in paediatric cardiology
DEFF Research Database (Denmark)
Smith, Julie; Goetze, Jens P; Andersen, Claus B;
diagnostic tools. Natriuretic peptide measurements could be that extra tool. We discuss and suggest N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide reference intervals for children without cardiovascular disease and cut-off points for the four specific paediatric heart conditions. We...
Novel Zn2+-chelating peptides selected from a fimbria-displayed random peptide library
DEFF Research Database (Denmark)
Kjærgaard, Kristian; Schembri, Mark; Klemm, Per
H adhesin. FimH is a component of the fimbrial organelle that can accommodate and display a diverse range of peptide sequences on the E. coli cell surface. In this study we have constructed a random peptide library in FimH. The library, consisting of similar to 40 million individual clones, was screened for...... completely novel Zn2+-binding peptide sequences had been isolated. By changing the protein scaffold system, we demonstrated that the Zn2+-binding seems to be uniquely mediated by the peptide insert and to be independent of the sequence of the carrier protein. These findings might be applied in the design of...... biomatrices for bioremediation purposes or in the development of sensors for detection of heavy metals....
Peptide specific expansion of CD8(+) T cells by recombinant plate bound MHC/peptide complexes
DEFF Research Database (Denmark)
Schmidt, Esben G W; Buus, Soren; Thorn, Mette;
in vitro T cell stimulation was investigated. By use of an antigenic peptide derived from the cytomegalovirus (CMVp) we tested the stimulatory efficacy of recombinant plate bound MHC molecules (PB-MHC), being immobilized in culture plates. A single stimulation of non-adherent peripheral blood...... effect of new stimulatory cocktails, e.g. cytokines and co-stimulatory molecules, by use of the present rapid and easy-to-use method of expanding peptide specific T cells.......Development of methods for efficient in vitro stimulation and expansion of peptide specific CD8(+) T cells is compelling not only with respect to adoptive T cell therapy but also regarding analysis of T cell responses and search for new immunogenic peptides. In the present study, a new approach to...
Metabolism and pharmacokinetic of cyclo-peptides and peptides. Use of radioelement and stable isotopes
International Nuclear Information System (INIS)
More and more peptides and proteins are used in therapeutic. Three mainly techniques are used for pharmacokinetic and metabolism studies: immunoassay, radioactively labeled molecules and mass spectrometry. In the first part of this work, we have used uniformly labelled peptides (C-peptide and insulin) with stables (13C, 15N, and 13C/15N) or radioactive (14C) isotopes to investigated these kind of studies. These works are based on isotope dilution mass spectrometry assay. In a second time we have investigated the metabolism of a particular cyclo-peptides families composed of two amino acids: the diketo-piperazine. These compounds are found in mammals and in microorganisms. There are not recognized by proteolytic enzymes. We have estimated if the main enzymes implicated in the metabolism of xenobiotics, the P450 cytochrome mono-oxygenases, were able to recognized them
Peptide Amphiphiles in Corneal Tissue Engineering
Directory of Open Access Journals (Sweden)
Martina Miotto
Full Text Available The increasing interest in effort towards creating alternative therapies have led to exciting breakthroughs in the attempt to bio-fabricate and engineer live tissues. This has been particularly evident in the development of new approaches applied to reconstruct corneal tissue. The need for tissue-engineered corneas is largely a response to the shortage of donor tissue and the lack of suitable alternative biological scaffolds preventing the treatment of millions of blind people worldwide. This review is focused on recent developments in corneal tissue engineering, specifically on the use of self-assembling peptide amphiphiles for this purpose. Recently, peptide amphiphiles have generated great interest as therapeutic molecules, both in vitro and in vivo. Here we introduce this rapidly developing field, and examine innovative applications of peptide amphiphiles to create natural bio-prosthetic corneal tissue in vitro. The advantages of peptide amphiphiles over other biomaterials, namely their wide range of functions and applications, versatility, and transferability are also discussed to better understand how these fascinating molecules can help solve current challenges in corneal regeneration.
Immunodiagnosis of parasitic diseases with synthetic peptides.
Noya, O; Patarroyo, M E; Guzmán, F; Alarcón de Noya, B
Parasitic diseases remain as a major public health problem worldwide, not only based on their historically high morbidity and mortality rates, but also because risk factors associated with their transmission are increasing. Laboratory diagnosis and particularly immunodiagnosis is a basic tool for the demonstration, clinical management and control of these infections. Classically, the serological tests for the detection of antibodies or antigens are based on the use of crude and purified antigens. Synthetic peptides have opened a new field and perspectives, as the source of pure epitopes and molecules for diagnosis of malaria, Chagas' disease, leishmaniasis, schistosomiasis, hidatidosis, cysticercosis and fasciolosis based on the detection of antibodies and circulating antigens. Herein, are critically reviewed the relevant advances and applications of the synthetic peptides on immunodiagnosis of parasitic diseases. A variety of sequences, constructs (monomers, polymers, MAPs), immunological methods and samples have been used, demonstrating their diagnostic potential. However, in most parasitic infections it is necessary to use more than a single peptide in order to avoid the genetic restriction against certain epitopes, as well as to test them in well characteized groups of patients, in order to confirm their sensitivity and specificity. The concept of multidiagnosis with synthetic peptides, using a novel multi-dot blot assay is introduced. Finally, the chemical imitation of antigens, offers a tremendous posibilities in the diagnosis of parasitic infections in developing countries since this strategy is cheaper, simpler, reproducible, useful for large scale testing and in most cases, specific and sensitive. PMID:14529537
Beyond Cell Penetrating Peptides: Designed Molecular Transporters
Wender, Paul A.; Cooley, Christina B.; Geihe, Erika I.
Inspired originally by peptides that traverse biological barriers, research on molecular transporters has since identified the key structural requirements that govern cellular entry, leading to new, significantly more effective and more readily available agents. These new drug delivery systems enable or enhance cellular and tissue uptake, can be targeted, and provide numerous additional advantages of significance in imaging, diagnostics and therapy.
Chemical labeling of electrochemically cleaved peptides
Roeser, Julien; Alting, Niels F. A.; Permentier, Hjalmar P.; Bruins, Andries P.; Bischoff, Rainer P. H.
RATIONALE Cleavage of peptide bonds C-terminal to tyrosine and tryptophan after electrochemical oxidation may become a complementary approach to chemical and enzymatic cleavage. A chemical labeling approach specifically targeting reactive cleavage products is presented here and constitutes a promisi
Computer-Aided Design of Antimicrobial Peptides
DEFF Research Database (Denmark)
Fjell, Christopher D.; Hancock, Robert E.W.; Jenssen, Håvard
An increasing number of reported cases of drug resistant Staphylococcus aureus and Pseudomonas aeruginosa, demonstrate the urgent need for new therapeutics that are effective against such and other multi-drug resistant bacteria. Antimicrobial peptides have for two decades now been looked upon as...
Stereocontrolled Synthesis of Methyl Silanediol Peptide Mimics
DEFF Research Database (Denmark)
Nielsen, Lone; Lindsay, Karl; Faber, Jesper;
methanolic HCl and the resulting amine extended into peptide chains accordingly. The diphenylsilyl moiety is a resilient protecting group for the corresponding silanediol, which can be unmasked via treatment with TfOH, followed by aqueous hydrolysis. The crude silanediol may be isolated and purified as its...
Apelin is a novel islet peptide
DEFF Research Database (Denmark)
Ringström, Camilla; Nitert, Marloes Dekker; Bennet, Hedvig;
Apelin, a recently discovered peptide with wide tissue distribution, regulates feeding behavior, improves glucose utilization, and inhibits insulin secretion. We examined whether apelin is expressed in human islets, as well as in normal and type 2 diabetic (T2D) animal islets. Further, we studied...
Kardiologiske aspekter af glukagonlignende peptid 1
DEFF Research Database (Denmark)
Elvekjaer, Mikkel; Engstrøm, Thomas; Jensen, Jan Skov; Treiman, Marek
Increasing experimental evidence points to direct effects of glucagon-like peptide-1 (GLP-1) and its analogs on the heart and circulatory system, in addition to the well-established, antidiabetic actions of these agents on glucose and on the energy metabolism. These effects are primarily...
Classification of antimicrobial peptides with imbalanced datasets
Camacho, Francy L.; Torres, Rodrigo; Ramos Pollán, Raúl
In the last years, pattern recognition has been applied to several fields for solving multiple problems in science and technology as for example in protein prediction. This methodology can be useful for prediction of activity of biological molecules, e.g. for determination of antimicrobial activity of synthetic and natural peptides. In this work, we evaluate the performance of different physico-chemical properties of peptides (descriptors groups) in the presence of imbalanced data sets, when facing the task of detecting whether a peptide has antimicrobial activity. We evaluate undersampling and class weighting techniques to deal with the class imbalance with different classification methods and descriptor groups. Our classification model showed an estimated precision of 96% showing that descriptors used to codify the amino acid sequences contain enough information to correlate the peptides sequences with their antimicrobial activity by means of learning machines. Moreover, we show how certain descriptor groups (pseudoaminoacid composition type I) work better with imbalanced datasets while others (dipeptide composition) work better with balanced ones.
Biofilm Induced Tolerance Towards Antimicrobial Peptides
DEFF Research Database (Denmark)
Folkesson, Anders; Haagensen, Janus Anders Juul; Zampaloni, Claudia;
presence of IncF plasmids expressing altered forms of the transfer pili in two different biofilm model systems. The mature biofilms were subsequently treated with two antibiotics with different molecular targets, the peptide antibiotic colistin and the fluoroquinolone ciprofloxacin. The dynamics of...
Ultrafast Hemithioindigo-based peptide-switches
Cordes, Thorben; Elsner, Cord; Herzog, Teja T.; Hoppmann, Christian; Schadendorf, Torsten; Summerer, Wolfram; Rück-Braun, Karola; Zinth, Wolfgang
Four newly synthesized Hemithioindigo-based peptide-switches with changing meta/para-substitution-pattern within the stilbene-part of the molecule are characterized with time-resolved absorption spectroscopy. The different substances undergo a light-induced Z/E-isomerization: the reaction proceeds o
Isolated Gramicidin Peptides Probed by IR Spectroscopy
Rijs, A. M.; Kabelac, M.; Abo-Riziq, A.; Hobza, P.; de Vries, M. S.
We report double-resonant IR/UV ion-dip spectroscopy of neutral gramicidin peptides in the gas phase. The IR spectra of gramicidin A and C, recorded in both the 1000 cm(-1) to 1800 cm(-1) and the 2700 to 3750 cm(-1) region, allow structural analysis. By studying this broad IR range, various local in
Exhaustively sampling peptide adsorption with metadynamics.
Deighan, Michael; Pfaendtner, Jim
Simulating the adsorption of a peptide or protein and obtaining quantitative estimates of thermodynamic observables remains challenging for many reasons. One reason is the dearth of molecular scale experimental data available for validating such computational models. We also lack simulation methodologies that effectively address the dual challenges of simulating protein adsorption: overcoming strong surface binding and sampling conformational changes. Unbiased classical simulations do not address either of these challenges. Previous attempts that apply enhanced sampling generally focus on only one of the two issues, leaving the other to chance or brute force computing. To improve our ability to accurately resolve adsorbed protein orientation and conformational states, we have applied the Parallel Tempering Metadynamics in the Well-Tempered Ensemble (PTMetaD-WTE) method to several explicitly solvated protein/surface systems. We simulated the adsorption behavior of two peptides, LKα14 and LKβ15, onto two self-assembled monolayer (SAM) surfaces with carboxyl and methyl terminal functionalities. PTMetaD-WTE proved effective at achieving rapid convergence of the simulations, whose results elucidated different aspects of peptide adsorption including: binding free energies, side chain orientations, and preferred conformations. We investigated how specific molecular features of the surface/protein interface change the shape of the multidimensional peptide binding free energy landscape. Additionally, we compared our enhanced sampling technique with umbrella sampling and also evaluated three commonly used molecular dynamics force fields. PMID:23706011
Application of Fungal Cyclic Peptides and Metabolites
Czech Academy of Sciences Publication Activity Database
Nedvěd, Jan; Šulc, Miroslav; Jegorov, A.; Giannakopulos, A.; Havlíček, Vladimír
Weinheim : Wiley, 2008 - (Van Eyk, J.; Dunn, M.), s. 483-509 ISBN 978-3-527-31637-3 R&D Projects: GA MŠk LC07017; GA ČR GA203/04/0799 Institutional research plan: CEZ:AV0Z50200510 Keywords : cyclic peptides * mass spectromety * fungal Subject RIV: EE - Microbiology, Virology
Method of producing a peptide mixture
DEFF Research Database (Denmark)
The present invention relates to a method for industrial production of a peptide preparation having specific specifications by hydrolysis of a protein material, preferably based on whey. The method comprises several steps, which makes it easy to control the method so as to obtain a product which, e...
Release of opioid peptides in anaesthetized cats?
Dashwood, M. R.; Feldberg, W.
1 The effect on arterial blood pressure of intravenous injections of naloxone (200 μg) was examined in cats anaesthetized with chloralose. Usually these injections have no effect on blood pressure unless morphine or opioid peptides have been injected, when they produce a pressor response with tachycardia.
Peptide Hormones in the Gastrointestinal Tract
DEFF Research Database (Denmark)
Rehfeld, Jens F.
Gastrointestinal hormones are peptides released from endocrine cells and neurons in the digestive tract. More than 30 hormone genes are currently known to be expressed in the gastrointestinal tract, which makes the gut the largest hormone-producing organ in the body. Modern biology makes it feasi...
Structural pattern matching of nonribosomal peptides
Directory of Open Access Journals (Sweden)
Leclère Valérie
Full Text Available Abstract Background Nonribosomal peptides (NRPs, bioactive secondary metabolites produced by many microorganisms, show a broad range of important biological activities (e.g. antibiotics, immunosuppressants, antitumor agents. NRPs are mainly composed of amino acids but their primary structure is not always linear and can contain cycles or branchings. Furthermore, there are several hundred different monomers that can be incorporated into NRPs. The NORINE database, the first resource entirely dedicated to NRPs, currently stores more than 700 NRPs annotated with their monomeric peptide structure encoded by undirected labeled graphs. This opens a way to a systematic analysis of structural patterns occurring in NRPs. Such studies can investigate the functional role of some monomeric chains, or analyse NRPs that have been computationally predicted from the synthetase protein sequence. A basic operation in such analyses is the search for a given structural pattern in the database. Results We developed an efficient method that allows for a quick search for a structural pattern in the NORINE database. The method identifies all peptides containing a pattern substructure of a given size. This amounts to solving a variant of the maximum common subgraph problem on pattern and peptide graphs, which is done by computing cliques in an appropriate compatibility graph. Conclusion The method has been incorporated into the NORINE database, available at http://bioinfo.lifl.fr/norine. Less than one second is needed to search for a pattern in the entire database.
Radiopharmaceuticals based on antibodies and peptides
International Nuclear Information System (INIS)
The past two decades have seen a great stride in the development of new diagnostic and therapeutic radiopharmaceuticals due to the discovery and availability of a number of specific carrier molecules and the application of synthetic organic chemistry to modify these carrier molecules to accommodate the radionuclide of interest. Radiopharmaceuticals based on antibodies and peptides are discussed
Novel properties of antimicrobial peptide anoplin
Czech Academy of Sciences Publication Activity Database
Jindřichová, Barbora; Burketová, Lenka; Novotná, Z.
Roč. 444, č. 4 (2014), s. 520-524. ISSN 0006-291X R&D Projects: GA ČR GA522/09/1693 Institutional support: RVO:61389030 Keywords : Anoplin * Antimicrobial peptide * Antifungal Subject RIV: EE - Microbiology, Virology Impact factor: 2.297, year: 2014
Selection of a peptide mimicking neutralization epitope of hepatitis E virus with phage peptide display technology
Institute of Scientific and Technical Information of China (English)
Ying Gu; Jun Zhang; Ying-Bing Wang; Shao-Wei Li; Hai-Jie Yang; Wen-Xin Luo; Ning-Shao Xia
AIM: To select the peptide mimicking the neutralization epitope of hepatitis E virus which bound to non-type-specific and conformational monoclonal antibodies (mAbs) 8C11 and 8H3 fromed 7-peptide phage display library, and expressed the peptide recombinant with HBcAg in E.coli, and to observe whether the recombinant HBcAg could still form virus like particle (VLP) and to test the activation of the recombinant polyprotein and chemo-synthesized peptide that was selected by mAb 8H3.METHODS: 8C11 and 8H3 were used to screen for binding peptides through a 7-peptide phage display library. After 4rounds of panning, monoclonal phages were selected and sequenced. The obtained dominant peptide coding sequences was then synthesized and inserted into amino acid 78 to 83 of hepatitis B core antigen (HBcAg), and then expressed in E. coli. Activity of the recombinant proteins was detected by Western blotting, VLPs of the recombinant polyproteins were tested by transmission electron microscopy and binding activity of the chemo-synthesized peptide was confirmed by BIAcore biosensor.RESULTS: Twenty-one positive monoclonal phages (10for 8CL1, and 11 for 8H3) were selected and the inserted fragments were sequenced. The DNA sequence coding for the obtained dominant peptides 8C11 (N′-His-Pro-Thr-LeuLeu-Arg-Ile-C′, named 8C11A) and 8H3 (N′-Ser-Ile-LeuPro- Tyr-Pro-Tyr-C′, named 8H3A) were then synthesized and cloned to the HBcAg vector, then expressed in E. coli.The recombinant proteins aggregated into homodimer or polymer on SDS-PAGE, and could bind to mAb 8C11 and 8H3 in Western blotting. At the same time, the recombinant polyprotein could form virus like particles (VLPs), which could be visualized on electron micrograph. The dominant peptide 8H3A selected by mAb 8H3 was further chemosynthesized, and its binding to mAb 8H3 could be detected by BIAcore biosensor.CONCLUSION: These results implicate that conformational neutralizing epitope can be partially modeled by a short
A Cocoa Peptide Protects Caenorhabditis elegans from Oxidative Stress and β-Amyloid Peptide Toxicity
Martorell, Patricia; Bataller, Esther; Llopis, Silvia; Gonzalez, Núria; Álvarez, Beatriz; Montón, Fernando; Ortiz, Pepa; Ramón, Daniel; Genovés, Salvador
Background Cocoa and cocoa-based products contain different compounds with beneficial properties for human health. Polyphenols are the most frequently studied, and display antioxidant properties. Moreover, protein content is a very interesting source of antioxidant bioactive peptides, which can be used therapeutically for the prevention of age-related diseases. Methodology/Principal Findings A bioactive peptide, 13L (DNYDNSAGKWWVT), was obtained from a hydrolyzed cocoa by-product by chromatog...
Natriuretic peptide receptors in the fetal rat.
Brown, J; Zuo, Z
In vitro autoradiography of rat fetuses from embryonic days 12-19 (E12-E19) showed widespread high-affinity specific binding sites for natriuretic peptides. The sites on E16 somites avidly bound C-type natriuretic peptide [CNP-(1-22)] as well as C-ANP, a synthetic ligand that selects the C-type natriuretic peptide receptor (NPR-C). Most somitic binding sites had high affinity for atrial natriuretic peptide [ANP-(1-28)], confirming their resemblance to NPR-C. A few had a lower apparent affinity for ANP-(1-28), suggesting that they might be NPR-B. CNP-(1-22) was more powerful than ANP-(1-28) as an agonist of guanosine 3',5'-cyclic monophosphate production in somites, and ATP augmented the action of CNP-(1-22). These observations further suggest the presence of NPR-B. However, with cross-linking of 3-[125I]iodo-0-tyrosyl rat CNP-(1-22) to somitic membranes followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, only a single 64-kDa binding protein was detected under reducing conditions. This is not consistent with intact approximately 120-kDa NPR-B. In vitro autoradiography of the binding of natriuretic peptides to E16 liver implied the presence of NPR-A and NPR-C-like receptors. Hepatic guanosine 3',5'-cyclic monophosphate production was most powerfully stimulated by ANP-(1-28), as expected for NPR-A. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis also identified NPR-A and NPR-C-like proteins in E16 hepatic membranes. Thus different NPRs are expressed by specific fetal tissues. This may be developmentally significant. PMID:7653543
Synthesis of peptide thioacids at neutral pH using bis(2-sulfanylethyl)amido peptide precursors.
Pira, Silvain L; Boll, Emmanuelle; Melnyk, Oleg
Reaction of bis(2-sulfanylethyl)amido (SEA) peptides with triisopropylsilylthiol in water at neutral pH yields peptide thiocarboxylates. An alkylthioester derived from β-alanine was used to trap the released bis(2-sulfanylethyl)amine and displace the equilibrium toward the peptide thiocarboxylate. PMID:24073852
A cardioactive peptide from the southern armyworm, Spodoptera eridania.
Furuya, K; Hackett, M; Cirelli, M A; Schegg, K M; Wang, H; Shabanowitz, J; Hunt, D F; Schooley, D A
A cardioactive peptide was isolated from extracts of whole heads of the southern armyworm, Spodoptera eridania. This peptide has the sequence ENFAVGCTPGYQRTADGRCKPTF (Mr = 2516.8), determined from both Edman sequencing and tandem mass spectrometry in combination with off-line micropreparative capillary liquid chromatography. This peptide, termed Spoer-CAP23, has excitatory effects on a semi-isolated heart from larval Manduca sexta, causing an inotropic effect at low concentrations of peptide and chronotropic and inotropic effects at high doses. The threshold concentration for stimulatory effects of the synthetic peptide on the semi-isolated heart was about 1 nM, suggesting a physiological role as a neuropeptide. PMID:10098624
Molecular imaging of cancer with radiolabeled peptides and PET.
Vāvere, Amy L; Rossin, Raffaella
Radiolabeled peptides hold promise for diagnosis and therapy of cancer as well as for early monitoring of therapy outcomes, patient stratification, etc. This manuscript focuses on the development of peptides labeled with 18F, 64Cu, 68Ga and other positron-emitting radionuclides for PET imaging. The major techniques for radionuclide incorporation are briefly discussed. Then, examples of positron-emitting peptides targeting somatostatin receptors, integrins, gastrin-releasing peptide receptors, vasointestinal peptide receptors, melanocortin 1 receptors and others are reviewed. PMID:22292762
Peptide-Loaded Solid Lipid Nanoparticles Prepared through Coacervation Technique
Directory of Open Access Journals (Sweden)
Marina Gallarate
Full Text Available Stearic acid solid lipid nanoparticles were prepared according to a new technique, called coacervation. The main goal of this experimental work was the entrapment of peptide drugs into SLN, which is a difficult task, since their chemical characteristics (molecular weight, hydrophilicity, and stability hamper peptide-containing formulations. Insulin and leuprolide, chosen as model peptide drugs, were encapsulated within nanoparticles after hydrophobic ion pairing with anionic surfactants. Peptide integrity was maintained after encapsulation, and nanoparticles can act in vitro as a sustained release system for peptide.
Cell-penetrating peptides transport therapeutics into cells.
Ramsey, Joshua D; Flynn, Nicholas H
Nearly 30years ago, certain small, relatively nontoxic peptides were discovered to be capable of traversing the cell membrane. These cell-penetrating peptides, as they are now called, have been shown to not only be capable of crossing the cell membrane themselves but can also carry many different therapeutic agents into cells, including small molecules, plasmid DNA, siRNA, therapeutic proteins, viruses, imaging agents, and other various nanoparticles. Many cell-penetrating peptides have been derived from natural proteins, but several other cell-penetrating peptides have been developed that are either chimeric or completely synthetic. How cell-penetrating peptides are internalized into cells has been a topic of debate, with some peptides seemingly entering cells through an endocytic mechanism and others by directly penetrating the cell membrane. Although the entry mechanism is still not entirely understood, it seems to be dependent on the peptide type, the peptide concentration, the cargo the peptide transports, and the cell type tested. With new intracellular disease targets being discovered, cell-penetrating peptides offer an exciting approach for delivering drugs to these intracellular targets. There are hundreds of cell-penetrating peptides being studied for drug delivery, and ongoing studies are demonstrating their success both in vitro and in vivo. PMID:26210404
Towards Identify Selective Antibacterial Peptides Based on Abstracts Meaning.
Barbosa-Santillán, Liliana I; Sánchez-Escobar, Juan J; Calixto-Romo, M Angeles; Barbosa-Santillán, Luis F
We present an Identify Selective Antibacterial Peptides (ISAP) approach based on abstracts meaning. Laboratories and researchers have significantly increased the report of their discoveries related to antibacterial peptides in primary publications. It is important to find antibacterial peptides that have been reported in primary publications because they can produce antibiotics of different generations that attack and destroy the bacteria. Unfortunately, researchers used heterogeneous forms of natural language to describe their discoveries (sometimes without the sequence of the peptides). Thus, we propose that learning the words meaning instead of the antibacterial peptides sequence is possible to identify and predict antibacterial peptides reported in the PubMed engine. The ISAP approach consists of two stages: training and discovering. ISAP founds that the 35% of the abstracts sample had antibacterial peptides and we tested in the updated Antimicrobial Peptide Database 2 (APD2). ISAP predicted that 45% of the abstracts had antibacterial peptides. That is, ISAP found that 810 antibacterial peptides were not classified like that, so they are not reported in APD2. As a result, this new search tool would complement the APD2 with a set of peptides that are candidates to be antibacterial. Finally, 20% of the abstracts were not semantic related to APD2. PMID:27366202
Peptides Interfering 3A Protein Dimerization Decrease FMDV Multiplication.
Directory of Open Access Journals (Sweden)
Mónica González-Magaldi
Full Text Available Nonstructural protein 3A is involved in relevant functions in foot-and-mouth disease virus (FMDV replication. FMDV 3A can form homodimers and preservation of the two hydrophobic α-helices (α1 and α2 that stabilize the dimer interface is essential for virus replication. In this work, small peptides mimicking residues involved in the dimer interface were used to interfere with dimerization and thus gain insight on its biological function. The dimer interface peptides α1, α2 and that spanning the two hydrophobic α-helices, α12, impaired in vitro dimer formation of a peptide containing the two α-helices, this effect being higher with peptide α12. To assess the effect of dimer inhibition in cultured cells, the interfering peptides were N-terminally fused to a heptaarginine (R7 sequence to favor their intracellular translocation. Thus, when fused to R7, interference peptides (100 μM were able to inhibit dimerization of transiently expressed 3A, the higher inhibitions being found with peptides α1 and α12. The 3A dimerization impairment exerted by the peptides correlated with significant, specific reductions in the viral yield recovered from peptide-treated FMDV infected cells. In this case, α2 was the only peptide producing significant reductions at concentrations lower than 100 μM. Thus, dimer interface peptides constitute a tool to understand the structure-function relationship of this viral protein and point to 3A dimerization as a potential antiviral target.
De-novo design of antimicrobial peptides for plant protection.
Directory of Open Access Journals (Sweden)
Benjamin Zeitler
Full Text Available This work describes the de-novo design of peptides that inhibit a broad range of plant pathogens. Four structurally different groups of peptides were developed that differ in size and position of their charged and hydrophobic clusters and were assayed for their ability to inhibit bacterial growth and fungal spore germination. Several peptides are highly active at concentrations between 0,1 and 1 µg/ml against plant pathogenic bacteria, such as Pseudomonas syringae, Pectobacterium carotovorum, and Xanthomonas vesicatoria. Importantly, no hemolytic activity could be detected for these peptides at concentrations up to 200 µg/ml. Moreover, the peptides are also active after spraying on the plant surface demonstrating a possible way of application. In sum, our designed peptides represent new antimicrobial agents and with the increasing demand for antimicrobial compounds for production of "healthy" food, these peptides might serve as templates for novel antibacterial and antifungal agents.
Tityus serrulatus venom peptidomics: assessing venom peptide diversity.
Rates, Breno; Ferraz, Karla K F; Borges, Márcia H; Richardson, Michael; De Lima, Maria Elena; Pimenta, Adriano M C
MALDI-TOF-TOF and de novo sequencing were employed to assess the Tityus serrulatus venom peptide diversity. Previous works has shown the cornucopia of molecular masses, ranging from 800 to 3000Da, present in the venom from this and other scorpions species. This work reports the identification/sequencing of several of these peptides. The majority of the peptides found were fragments of larger venom toxins. For instance, 28 peptides could be identified as fragments from Pape proteins, 10 peptides corresponded to N-terminal fragments of the TsK beta (scorpine-like) toxin and fragments of potassium channel toxins (other than the k-beta) were sequenced as well. N-terminal fragments from the T. serrulatus hypotensins-I and II and a novel hypotensin-like peptide could also be found. This work also reports the sequencing of novel peptides without sequence similarities to other known molecules. PMID:18718845
Bicyclic Peptide Inhibitor of Urokinase-Type Plasminogen Activator
DEFF Research Database (Denmark)
Roodbeen, Renée; Paaske, Berit; Jiang, Longguang;
The development of protease inhibitors for pharmacological intervention has taken a new turn with the use of peptidebased inhibitors. Here, we report the rational design of bicyclic peptide inhibitors of the serine protease urokinase-type plasminogen activator (uPA), based on the established...... monocyclic peptide, upain-2. It was successfully converted to a bicyclic peptide, without loss of inhibitory properties. The aim was to produce a peptide cyclised by an amide bond with an additional stabilising across-the-ring covalent bond. We expected this bicyclic peptide to exhibit a lower entropic...... burden upon binding. Two bicyclic peptides were synthesised with affinities similar to that of upain-2, and their binding energetics were evaluated by isothermal titration calorimetry. Indeed, compared to upain-2, the bicyclic peptides showed reduced loss of entropy upon binding to uPA. We also...
Enzymatic digestibility of peptides cross-linked by ionizing radiation
International Nuclear Information System (INIS)
Digestibility by proteolytic enzymes of peptides cross-linked by ionizing radiation was investigated. Small peptides of alanine and phenylalanine were chosen as model compounds and aminopeptidases and carboxypeptidases were used as proteolytic enzymes. Peptides exposed to γ-radiation in aqueous solution were analysed by high-performance liquid chromatography before and after hydrolysis by aminopeptidase M, leucine aminopeptidase carboxypeptidase A and carboxypeptidase Y. The results obtained clearly demonstrate the different actions of these enzymes on cross-linked aliphatic and aromatic peptides. Peptide bonds of cross-linked dipeptides of alanine were completely resistant to enzymatic hydrolysis whereas the enzymes, except for carboxypeptidase Y, cleaved all peptide bonds of cross-linked peptides of phenylalanine. The actions of the enzymes on these particular compounds are discussed in detail. (author)
Inhibition of aggregation of amyloid peptides by beta-sheet breaker peptides and their binding affinity.
Viet, Man Hoang; Ngo, Son Tung; Lam, Nguyen Sy; Li, Mai Suan
The effects of beta-sheet breaker peptides KLVFF and LPFFD on the oligomerization of amyloid peptides were studied by all-atom simulations. It was found that LPFFD interferes the aggregation of Aβ(16-22) peptides to a greater extent than does KLVFF. Using the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method, we found that the former binds more strongly to Aβ(16-22). Therefore, by simulations, we have clarified the relationship between aggregation rates and binding affinity: the stronger the ligand binding, the slower the oligomerization process. The binding affinity of pentapeptides to full-length peptide Aβ(1-40) and its mature fibrils has been considered using the Autodock and MM-PBSA methods. The hydrophobic interaction between ligands and receptors plays a more important role for association than does hydrogen bonding. The influence of beta-sheet breaker peptides on the secondary structures of monomer Aβ(1-40) was studied in detail, and it turns out that, in their presence, the total beta-sheet content can be enhanced. However, the aggregation can be slowed because the beta-content is reduced in fibril-prone regions. Both pentapeptides strongly bind to monomer Aβ(1-40), as well as to mature fibrils, but KLVFF displays a lower binding affinity than LPFFD. Our findings are in accord with earlier experiments that both of these peptides can serve as prominent inhibitors. In addition, we predict that LPFFD inhibits/degrades the fibrillogenesis of full-length amyloid peptides better than KLVFF. This is probably related to a difference in their total hydrophobicities in that the higher the hydrophobicity, the lower the inhibitory capacity. The GROMOS96 43a1 force field with explicit water and the force field proposed by Morris et al. (Morris et al. J. Comput. Chem. 1998, 19, 1639 ) were employed for all-atom molecular dynamics simulations and Autodock experiments, respectively. PMID:21563780
Drosophila suzukii contains a peptide homologous to the Drosophila melanogaster sex-peptide and functional in both species.
Schmidt, T; Choffat, Y; Schneider, M; Hunziker, P; Fuyama, Y; Kubli, E
A peptide homologous to the Drosophila melanogaster sex-peptide (SP) was isolated from Drosophila suzukii accessory glands and its amino acid sequence determined. The D. suzukii peptide contains 41 amino acids and has a calculated molecular weight of 5100 Da. Comparison of the sequences reveals strong homologies in the N-terminal and C-terminal parts of the peptides. In the D. suzukii sex-peptide, however, five additional amino acids are inserted after amino acid 7. Based on the sequence of the peptide, a cDNA coding for the D. suzukii peptide was isolated by PCR. Sequence analysis of the cDNA confirmed the SP amino acid sequence determined by peptide sequencing. Furthermore, based on the cDNA sequence, we isolated the D. suzukii sex-peptide gene by inverse PCR. The D. suzukii sex-peptide gene contains an intron and codes for a 60 amino acid precursor. The D. melanogaster and the D. suzuki sex-peptides elicit rejection behaviour in the presence of males and an increased egg laying in virgin females of both species. PMID:8353518
Biodegradable Polyphosphazene Based Peptide-Polymer Hybrids
Directory of Open Access Journals (Sweden)
Anne Linhardt
Full Text Available A novel series of peptide based hybrid polymers designed to undergo enzymatic degradation is presented, via macrosubstitution of a polyphosphazene backbone with the tetrapeptide Gly-Phe-Leu-Gly. Further co-substitution of the hybrid polymers with hydrophilic polyalkylene oxide Jeffamine M-1000 leads to water soluble and biodegradable hybrid polymers. Detailed degradation studies, via 31P NMR spectroscopy, dynamic light scattering and field flow fractionation show the polymers degrade via a combination of enzymatic, as well as hydrolytic pathways. The peptide sequence was chosen due to its known property to undergo lysosomal degradation; hence, these degradable, water soluble polymers could be of significant interest for the use as polymer therapeutics. In this context, we investigated conjugation of the immune response modifier imiquimod to the polymers via the tetrapeptide and report the self-assembly behavior of the conjugate, as well as its enzymatically triggered drug release behavior.
Novel peptide-based protease inhibitors
DEFF Research Database (Denmark)
Roodbeen, Renée
This thesis describes the design and synthesis of peptide-based serine protease inhibitors. The targeted protease, urokinase-type plasminogen activator (uPA) activates plasminogen, which plays a major role in cancer metastasis. The peptide upain-2 (S 1 ,S 12-cyclo-AcCSWRGLENHAAC-NH2) is a highly...... specific inhibitor of uPA. With the aim of creating better inhibitors based on the upain-2 scaffold, the following three strategies were explored: First, it was attempted to predefine the structure of upain-2 in solution by incorporating turn-inducing sequences and peptidomimetics. Additionally...... bond across the ring. The second bridge was made by a disulfide bridge, amide bond formation or via ring-closing metathesis. A, with upain-2 equipotent, bicyclic inhibitor was obtained and its binding to uPA was studied by ITC, NMR and X-ray. The knowledge of how selective inhibitors bind uPA has been...
Peptides for radiotherapy of neuroendocrine cancers
International Nuclear Information System (INIS)
During the last decade there has been a resurgence of interest in therapeutic nuclear medicine, due to the limitation of conventional or external beam radiotherapy in the treatment of secondary or metastatic cancer sites outside of the primary treatment area. Some of the human tumours that produce metastases express high levels of somatostatin receptors. In order to make possible the diagnostic and radiotherapeutic treatment of these kind of tumours, various somatostatin analogue peptides have been developed in recent years. Peptides have become an important class of radiopharmaceuticals,due to its unique ability to detect specific sites as receptors or enzymes. This paper describes the work with 99m Tc to establish the labelling and analytical conditions for a somatostatin analogue as a precursor, to undertake a therapeutic radiopharmaceutical labelled with 188 Re for treatment of somatostatin receptor positive tumours. (Author)
Bacterial strategies of resistance to antimicrobial peptides.
Joo, Hwang-Soo; Fu, Chih-Iung; Otto, Michael
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160595
Peptide catalysed prebiotic polymerization of RNA
DEFF Research Database (Denmark)
Wieczorek, Rafal; Luisi, Pier Luigi; Monnard, Pierre-Alain
A short peptide composed of only two amino acid residues, serine and histidine, is here reported to enable oligomerization of RNA monomers. SerHis dipeptide was previously reported to catalyse formation of peptide bonds (Gorlero et al. 2009) as well as possessing broad hydrolytic activities...... oligomers from imidazole derivatives of mononucleotides. The thermodynamic shift towards condensation was achieved using water/ice eutectic phase environment (Monnard and Ziock 2008). To obtain such an environment, a reaction solution is cooled below its freezing point, but above the eutectic point. Under....... (2000) Dipeptide seryl-histidine and related oligopeptides cleave DNA, protein, and a carboxyl ester. Bioorg. Med. Chem. 8(12): 2675-80. Monnard PA, Ziock H. (2008) Eutectic phase in water-ice: a self-assembled environment conducive to metal-catalyzed non-enzymatic RNA polymerization. Chem Biodivers. 5...
Secondary structure of fluorescence labelled synthetic peptides
Martin, A S
A series of eight synthetic oligopeptides has been prepared and their secondary structures investigated using various techniques. The project represents a continuation of an investigation into thermally induced changes in secondary structure. Following the previously reported results, the change in structure was initially thought to represent a change from an alpha-helix at low temperature to 3 sub 1 sub 0 -helix at high temperature. However, the results reported herein suggest the peptides retain an alpha-helical configuration at all temperatures studied, but that this helix can adopt at least two related forms. The difference in the structures relates to the nature of the H-bonds which may or may not involve an additional interaction from water molecules or side-chains. The peptides were encouraged to adopt a helical configuration by the inclusion of alpha- aminoisobutyric acid (Aib) residues. Also, modified forms of glutamic acid were included in the sequences. These had pendant donor (4-methoxy naphthalen...
Ion Mobility Separation of Peptide Isotopomers
Kaszycki, Julia L.; Bowman, Andrew P.; Shvartsburg, Alexandre A.
Differential or field asymmetric waveform ion mobility spectrometry (FAIMS) operating at high electric fields fully resolves isotopic isomers for a peptide with labeled residues. The naturally present isotopes, alone and together with targeted labels, also cause spectral shifts that approximately add for multiple heavy atoms. Separation qualitatively depends on the gas composition. These findings may enable novel strategies in proteomic and metabolomic analyses using stable isotope labeling.
Spider-Venom Peptides as Therapeutics
Glenn F King; Volker Herzig; Rash, Lachlan D; Jensen, Jonas E.; Sing Yan Er; Sebastian Senff; Saez, Natalie J.
Spiders are the most successful venomous animals and the most abundant terrestrial predators. Their remarkable success is due in large part to their ingenious exploitation of silk and the evolution of pharmacologically complex venoms that ensure rapid subjugation of prey. Most spider venoms are dominated by disulfide-rich peptides that typically have high affinity and specificity for particular subtypes of ion channels and receptors. Spider venoms are conservatively predicted to contain more ...
Amyloid beta peptide immunotherapy in Alzheimer disease.
Delrieu, J; Ousset, P J; Voisin, T; Vellas, B
Recent advances in the understanding of Alzheimer's disease pathogenesis have led to the development of numerous compounds that might modify the disease process. Amyloid β peptide represents an important molecular target for intervention in Alzheimer's disease. The main purpose of this work is to review immunotherapy studies in relation to the Alzheimer's disease. Several types of amyloid β peptide immunotherapy for Alzheimer's disease are under investigation, active immunization and passive administration with monoclonal antibodies directed against amyloid β peptide. Although immunotherapy approaches resulted in clearance of amyloid plaques in patients with Alzheimer's disease, this clearance did not show significant cognitive effect for the moment. Currently, several amyloid β peptide immunotherapy approaches are under investigation but also against tau pathology. Results from amyloid-based immunotherapy studies in clinical trials indicate that intervention appears to be more effective in early stages of amyloid accumulation in particular solanezumab with a potential impact at mild Alzheimer's disease, highlighting the importance of diagnosing Alzheimer's disease as early as possible and undertaking clinical trials at this stage. In both phase III solanezumab and bapineuzumab trials, PET imaging revealed that about a quarter of patients lacked fibrillar amyloid pathology at baseline, suggesting that they did not have Alzheimer's disease in the first place. So a new third phase 3 clinical trial for solanezumab, called Expedition 3, in patients with mild Alzheimer's disease and evidence of amyloid burden has been started. Thus, currently, amyloid intervention is realized at early stage of the Alzheimer's disease in clinical trials, at prodromal Alzheimer's disease, or at asymptomatic subjects or at risk to develop Alzheimer's disease and or at asymptomatic subjects with autosomal dominant mutation. PMID:25459121
Physics and engineering of peptide supramolecular nanostructures.
Handelman, Amir; Beker, Peter; Amdursky, Nadav; Rosenman, Gil
The emerging "bottom-up" nanotechnology reveals a new field of bioinspired nanomaterials composed of chemically synthesized biomolecules. They are formed from elementary constituents in supramolecular structures by the use of a developed nature self-assembly mechanism. The focus of this perspective paper is on intrinsic fundamental physical properties of bioinspired peptide nanostructures and their small building units linked by weak noncovalent bonds. The observed exceptional optical properties indicate a phenomenon of quantum confinement in these supramolecular structures, which originates from nanoscale size of their elementary building blocks. The dimensionality of the confinement gives insight into intrinsic packing of peptide supramolecular nanomaterials. QC regions, revealed in bioinspired nanostructures, were found by us in amyloid fibrils formed from insulin protein. We describe ferroelectric and related properties found at the nanoscale based on original crystalline asymmetry of the nanoscale building blocks, packing these structures. In this context, we reveal a classic solid state physics phenomenon such as reconstructive phase transition observed in bioorganic peptide nanotubes. This irreversible phase transformation leads to drastic reshaping of their quantum structure from quantum dots to quantum wells, which is followed by variation of their space group symmetry from asymmetric to symmetric. We show that the supramolecular origin of these bioinspired nanomaterials provides them a unique chance to be disassembled into elementary building block peptide nanodots of 1-2 nm size possessing unique electronic, optical and ferroelectric properties. These multifunctional nanounits could lead to a new future step in nanotechnology and nanoscale advanced devices in the fields of nanophotonics, nanobiomedicine, nanobiopiezotronics, etc. PMID:22460950
Immunological responses to fungal epitope peptides
Sheth-Ughade, Parita
Introduction: Fungi are common aeroallergens responsible for at least 3% – 10% of allergic diseases worldwide, with the proportion hugely variable in different populations. Treatment is complicated by viable nature and disease causing ability of the allergen and is often only palliative. Thus, this study aimed to serve as a pilot investigation to design novel anti-allergy therapeutics to cure allergy at the molecular level. It investigates the effect of wild type fungal peptides and correspon...
Antimicrobial peptides from plants and insects
Czech Academy of Sciences Publication Activity Database
Macková, Martina; Doležílková, Ivana; Neubauerová, Tereza; Ciencialová, Alice; Macek, Tomáš; Koutek, Bohumír; Jiráček, Jiří
Roč. 7, č. 2 (2007), s. 26-27. ISSN 1213-6670. [Konference experimentální biologie rostlin, dny fyziologie rostlin /11./. 09.07.2007-12.07.2007, Olomouc] R&D Projects: GA ČR GA203/05/0832 Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * RP-HPLC * screening * fleshfly Subject RIV: CC - Organic Chemistry
Application of Fungal Cyclic Peptides and Metabolites
Czech Academy of Sciences Publication Activity Database
Nedvěd, Jan; Šulc, Miroslav; Jegorov, A.; Giannakopulos, A.; Havlíček, Vladimír
Weinheim : Wiley, 2007 - (Van Eyk, J.; Dunn, M.), s. 483-498 ISBN 978-3-527-31637-3 R&D Projects: GA MŠk LC07017; GA ČR GA203/04/0799 Grant ostatní: XE(XE) EK MTKD-CT-2004-014407 Institutional research plan: CEZ:AV0Z50200510 Source of funding: R - rámcový projekt EK Keywords : cyclic * fungal * peptides Subject RIV: EE - Microbiology, Virology
Separation of Peptides by Pressurized Capillary Electrochromatography
Institute of Scientific and Technical Information of China (English)
A novel gradient pressurized capillary electrochromatography (pCEC) instrument wasdeveloped to separate peptides. Two gradient elution modes, hydrophobic and hydrophilicinteraction mode in pCEC, were performed on this instrument. Baseline separation of sixpeptides was obtained on two gradient modes with C18 column and strong cationic exchangecolumn respectively. The effects of mixer volume and total flow rate of pumps on resolutionwere also discussed.
Characterizing Intercellular Signaling Peptides in Drug Addiction
Romanova, Elena V.; Hatcher, Nathan G.; Rubakhin, Stanislav S.; Sweedler, Jonathan V.
Intercellular signaling peptides (SPs) coordinate the activity of cells and influence organism behavior. SPs, a chemically and structurally diverse group of compounds responsible for transferring information between neurons, are broadly involved in neural plasticity, learning and memory, as well as in drug addiction phenomena. Historically, SP discovery and characterization has tracked advances in measurement capabilities. Today, a suite of analytical technologies is available to investigate ...
Silica precipitation with synthetic silaffin peptides
Wieneke, Ralph; Bernecker, Anja; Riedel, Radostan; Sumper, Manfred; Steinem, Claudia; Geyer, Armin
Silaffins are highly charged proteins which are one of the major contributing compounds that are thought to be responsible for the formation of the hierarchically structured silica-based cell walls of diatoms. Here we describe the synthesis of an oligo-propyleneamine substituted lysine derivative and its incorporation into the KXXK peptide motif occurring repeatedly in silaffins. Ne-alkylation of lysine was achieved by a Mitsunobu reaction to obtain a protected lysine derivative w...
Glucagon-like peptides 1 and 2
DEFF Research Database (Denmark)
Kissow, Hannelouise
healing. The antidiabetic hormone GLP-1, cosecreted with GLP-2, diminished mucositis in an animal model of the condition. Therefore, both peptides could be involved in the pathophysiology of mucositis. SUMMARY: The intestinal GLPs have shown beneficial effects in experimental trials and have potential for...... therapeutic use. In type 2 diabetic and obese patients, GLP secretion is impaired. Elucidating the role of these endogenous hormones could lead to the identification of mucositis risk factors and an alternative preventive therapy for these patients....
SH3 domain-peptide binding energy calculations based on structural ensemble and multiple peptide templates.
Directory of Open Access Journals (Sweden)
Seungpyo Hong
Full Text Available SH3 domains mediate signal transduction by recognizing short peptides. Understanding of the driving forces in peptide recognitions will help us to predict the binding specificity of the domain-peptide recognition and to understand the molecular interaction networks of cells. However, accurate calculation of the binding energy is a tough challenge. In this study, we propose three ideas for improving our ability to predict the binding energy between SH3 domains and peptides: (1 utilizing the structural ensembles sampled from a molecular dynamics simulation trajectory, (2 utilizing multiple peptide templates, and (3 optimizing the sequence-structure mapping. We tested these three ideas on ten previously studied SH3 domains for which SPOT analysis data were available. The results indicate that calculating binding energy using the structural ensemble was most effective, clearly increasing the prediction accuracy, while the second and third ideas tended to give better binding energy predictions. We applied our method to the five SH3 targets in DREAM4 Challenge and selected the best performing method.
Mass spectrometric survey of peptides in cephalopods with an emphasis on the FMRFamide-related peptides.
Sweedler, J V; Li, L; Floyd, P; Gilly, W
A matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) survey of the major peptides in the stellar, fin and pallial nerves and the posterior chromatophore lobe of the cephalopods Sepia officinalis, Loligo opalescens and Dosidicus gigas has been performed. Although a large number of putative peptides are distinct among the three species, several molecular masses are conserved. In addition to peptides, characterization of the lipid content of the nerves is reported, and these lipid peaks account for many of the lower molecular masses observed. One conserved set of peaks corresponds to the FMRFamide-related peptides (FRPs). The Loligo opalescens FMRFa gene has been sequenced. It encodes a 331 amino acid residue prohormone that is processed into 14 FRPs, which are both predicted by the nucleotide sequence and confirmed by MALDI MS. The FRPs predicted by this gene (FMRFa, FLRFa/FIRFa and ALSGDAFLRFa) are observed in all three species, indicating that members of this peptide family are highly conserved across cephalopods. PMID:11060217
Screening Peptide Inhibitors Using Phage Peptide Library with Isocitrate Lyase in Mycobacterium tuberculosis as Target
Institute of Scientific and Technical Information of China (English)
YIN Yu-he; NIU Xue; SUN Bo; TENG Guo-sheng; ZHAO Yun-hui; WU Cong-mei
When devoured by macrophages,Mycobacterium tuberculosis remains persistent in macrophages and gains energy through the glyoxylate bypass to maintain its long-term existence in host cells.Therefore it is possible to stop persistent infections by interdicting the glyoxylate bypass in which the isocitrate lyase(ICL) is the key rate-limiting enzyme and a persistence factor.ICL is the target of anti-TB(TB:tubercular) drugs,which could screen ICL out and effectively inhibit the activity of ICL in Mycobacterium tuberculosis,and because of this,anti-TB drugs can be used to kill persistent Mycobacterium tuberculosis.In this study,the ICL gene of the Mycobacterium tuberculosis H37Rv was cloned successfully and recombinant protein with bioactivity was obtained through the enzyme characteristic appraisal.The specific activity of the recombined ICL is 24 μmol·mg-1 -min-1.The recombined ICL protein was used as the target,and phages which can specifically combine to ICL were screened in the phage 7 peptide library.According to the results of the ELISA and DNA sequence detection,eventually three 7-peptide chains were synthesized.Then the peptide chains were reacted with ICL,respectively,to detect their inhibitory effects on ICL.The results show that all the three 7-peptide chains possessed varying inhibitory effects on the activity of ICL.This study provided lead compounds for the research and development of new peptide anti-TB drugs.
C-peptide and Diabetic Encephalopathy
Institute of Scientific and Technical Information of China (English)
Xiao-jun Cai; Hui-qin Xu; Yi Lu
With the changes of life style, diabetes and its complications have become a major cause of morbidity and mortality. It is reasonable to anticipate a continued rise in the incidence of diabetes and its complications along with the aging of the population, increase in adult obesity rate, and other risk factors. Diabetic encephalopathy is one of the severe microvascular complications of diabetes, characterized by impaired cognitive functions, and electrophysiological, neurochemical, and structural abnormalities. It may involve direct neuronal damage caused by intracellular glucose. However, the pathogenesis of this disease is complex and its diagnosis is not very clear. Previous researches have suggested that chronic metabolic alterations, vascular changes, and neuronal apoptosis may play important roles in neuronal loss and damaged cognitive fimctions.Multiple factors are responsible for neuronal apoptosis, such as disturbed insulin growth factor (IGF) system,hyperglycemia, and the aging process. Recent data suggest that insulin/C-peptide defidency may exert a primary and key effect in diabetic encephalopathy. Administration of C-peptide partially improves the condition of the IGF system in the brain and prevents neuronal apoptosis in the hippocampus of diabetic patients.Those Findings provide a basis for application of C-peptide as a potentially effective therapy for diabetes and diabetic encephalopathy.
Potential Anticarcinogenic Peptides from Bovine Milk
Directory of Open Access Journals (Sweden)
Giacomo Pepe
Full Text Available Bovine milk possesses a protein system constituted by two major families of proteins: caseins (insoluble and whey proteins (soluble. Caseins (αS1, αS2, β, and κ are the predominant phosphoproteins in the milk of ruminants, accounting for about 80% of total protein, while the whey proteins, representing approximately 20% of milk protein fraction, include β-lactoglobulin, α-lactalbumin, immunoglobulins, bovine serum albumin, bovine lactoferrin, and lactoperoxidase, together with other minor components. Different bioactivities have been associated with these proteins. In many cases, caseins and whey proteins act as precursors of bioactive peptides that are released, in the body, by enzymatic proteolysis during gastrointestinal digestion or during food processing. The biologically active peptides are of particular interest in food science and nutrition because they have been shown to play physiological roles, including opioid-like features, as well as immunomodulant, antihypertensive, antimicrobial, antiviral, and antioxidant activities. In recent years, research has focused its attention on the ability of these molecules to provide a prevention against the development of cancer. This paper presents an overview of antitumor activity of caseins and whey proteins and derived peptides.
Antimicrobial peptides in echinoderm host defense.
Li, Chun; Blencke, Hans-Matti; Haug, Tor; Stensvåg, Klara
Antimicrobial peptides (AMPs) are important effector molecules in innate immunity. Here we briefly summarize characteristic traits of AMPs and their mechanisms of antimicrobial activity. Echinoderms live in a microbe-rich marine environment and are known to express a wide range of AMPs. We address two novel AMP families from coelomocytes of sea urchins: cysteine-rich AMPs (strongylocins) and heterodimeric AMPs (centrocins). These peptide families have conserved preprosequences, are present in both adults and pluteus stage larvae, have potent antimicrobial properties, and therefore appear to be important innate immune effectors. Strongylocins have a unique cysteine pattern compared to other cysteine-rich peptides, which suggests a novel AMP folding pattern. Centrocins and SdStrongylocin 2 contain brominated tryptophan residues in their native form. This review also includes AMPs isolated from other echinoderms, such as holothuroidins, fragments of beta-thymosin, and fragments of lectin (CEL-III). Echinoderm AMPs are crucial molecules for the understanding of echinoderm immunity, and their potent antimicrobial activity makes them potential precursors of novel drug leads. PMID:25445901
Hierarchical organization of ferrocene-peptides.
Beheshti, Samaneh; Martić, Sanela; Kraatz, Heinz-Bernhard
Hierarchical self-assembly of disubstituted ferrocene (Fc)-peptide conjugates that possess Gly-Val-Phe and Gly-Val-Phe-Phe peptide substituents leads to the formation of nano- and micro-sized assemblies. Hydrogen-bonding and hydrophobic interactions provide directionality to the assembly patterns. The self-assembling behavior of these compounds was studied in solution by using (1)H NMR and circular dichroism (CD) spectroscopies. In the solid state, attenuated total reflectance (ATR) FTIR spectroscopy, single-crystal X-ray diffraction (XRD), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM) methods were used. Spontaneous self-assembly of Fc-peptides through intra- and intermolecular hydrogen-bonding interactions induces supramolecular assemblies, which further associate and give rise to fibers, large fibrous crystals, and twisted ropes. In the case of Fc[CO-Gly-Val-Phe-OMe](2) (1), molecules initially interact to form pleated sheets that undergo association into long fibers that form bundles and rectangular crystalline cuboids. Molecular offsets and defects, such as screw dislocations and solvent effects that occur during crystal growth, induce the formation of helical arrangements, ultimately leading to large twisted ropes. By contrast, the Fc-tetrapeptide conjugate Fc[CO-Gly-Val-Phe-Phe-OMe](2) (2) forms a network of nanofibers at the supramolecular level, presumably due to the additional hydrogen-bonding and hydrophobic interactions that stem from the additional Phe residues. PMID:22707407
Potential anticarcinogenic peptides from bovine milk.
Pepe, Giacomo; Tenore, Gian Carlo; Mastrocinque, Raffaella; Stusio, Paola; Campiglia, Pietro
BOVINE MILK POSSESSES A PROTEIN SYSTEM CONSTITUTED BY TWO MAJOR FAMILIES OF PROTEINS: caseins (insoluble) and whey proteins (soluble). Caseins ( α S1, α S2, β , and κ ) are the predominant phosphoproteins in the milk of ruminants, accounting for about 80% of total protein, while the whey proteins, representing approximately 20% of milk protein fraction, include β -lactoglobulin, α -lactalbumin, immunoglobulins, bovine serum albumin, bovine lactoferrin, and lactoperoxidase, together with other minor components. Different bioactivities have been associated with these proteins. In many cases, caseins and whey proteins act as precursors of bioactive peptides that are released, in the body, by enzymatic proteolysis during gastrointestinal digestion or during food processing. The biologically active peptides are of particular interest in food science and nutrition because they have been shown to play physiological roles, including opioid-like features, as well as immunomodulant, antihypertensive, antimicrobial, antiviral, and antioxidant activities. In recent years, research has focused its attention on the ability of these molecules to provide a prevention against the development of cancer. This paper presents an overview of antitumor activity of caseins and whey proteins and derived peptides. PMID:23533710
Fingerprinting Desmosine-Containing Elastin Peptides
Schräder, Christoph U.; Heinz, Andrea; Majovsky, Petra; Schmelzer, Christian E. H.
Elastin is a vital protein of the extracellular matrix of jawed vertebrates and provides elasticity to numerous tissues. It is secreted in the form of its soluble precursor tropoelastin, which is subsequently cross-linked in the course of the elastic fiber assembly. The process involves the formation of the two tetrafunctional amino acids desmosine (DES) and isodesmosine (IDES), which are unique to elastin. The resulting high degree of cross-linking confers remarkable properties, including mechanical integrity, insolubility, and long-term stability to the protein. These characteristics hinder the structural elucidation of mature elastin. However, MS2 data of linear and cross-linked peptides released by proteolysis can provide indirect insights into the structure of elastin. In this study, we performed energy-resolved collision-induced dissociation experiments of DES, IDES, their derivatives, and DES-/IDES-containing peptides to determine characteristic product ions. It was found that all investigated compounds yielded the same product ion clusters at elevated collision energies. Elemental composition determination using the exact masses of these ions revealed molecular formulas of the type CxHyN, suggesting that the pyridinium core of DES/IDES remains intact even at relatively high collision energies. The finding of these specific product ions enabled the development of a similarity-based scoring algorithm that was successfully applied on LC-MS/MS data of bovine elastin digests for the identification of DES-/IDES-cross-linked peptides. This approach facilitates the straightforward investigation of native cross-links in elastin.
Peptides: Basic determinants of reproductive functions.
Celik, Onder; Aydin, Suleyman; Celik, Nilufer; Yilmaz, Musa
Mammalian reproduction is a costly process in terms of energy consumption. The critical information regarding metabolic status is signaled to the hypothalamus mainly through peripheral peptides from the adipose tissue and gastrointestinal tract. Changes in energy stores produce fluctuations in leptin, insulin, ghrelin and glucose signals that feedback mainly to the hypothalamus to regulate metabolism and fertility. In near future, possible effects of the nutritional status on GnRH regulation can be evaluated by measuring serum or tissue levels of leptin and ghrelin in patiens suffering from infertility. The fact that leptin and ghrelin are antagonistic in their effects on GnRH neurons, their respective agonistic and antagonistic roles make them ideal candidates to use instead of GnRH agonist and antagonist. Similarly, kisspeptin expressing neurons are likely to mediate the well-established link between energy balance and reproductive functions. Exogenous kisspeptin can be used for physiological ovarian hyperstimulation for in-vitro fertilization. Moreover, kisspeptin antagonist therapy can be used for the treatment of postmenapousal women, precocious puberty, PCOS, endometriosis and uterine fibroids. In this review, we will analyze the central mechanisms involved in the integration of metabolic information and their contribution to the control of the reproductive function. Particular attention will be paid to summarize the participation of leptin, kisspeptin, ghrelin, NPY, orexin, urocortin, VIP, insulin, galanin, galanin like peptide, oxytocin, agouti gene-related peptide, and POMC neurons in this process and their possible interactions to contribute to the metabolic control of reproduction. PMID:26074346
Multifunctional matrices for oral peptide delivery.
Bernkop-Schnürch, A; Walker, G
The oral administration of peptide drugs represents one of the greatest challenges in pharmaceutical technology. To gain a sufficient bioavailability of these therapeutic agents, various barriers including the mucus-layer barrier, the enzymatic barrier, and the membrane barrier have to be overcome. A promising strategy for achieving this goal is the use of multifunctional matrices. These matrices are based on polymers that display mucoadhesive properties, a permeation-enhancing effect, enzyme-inhibiting properties, and/or a high buffer capacity. Moreover, a sustained or delayed drug release can be provided by delivery systems that contain such polymers. Among them, polyacrylates, cellulose derivatives, and chitosan are promising excipients that can also be customized by chemical modification to improve certain properties. For example, the covalent attachment of thiol moieties on these polymers leads to improved mucoadhesive and permeation-enhancing properties, and the conjugation of enzyme inhibitors enables the matrices to provide protection for peptide drugs against enzymatic degradation. The efficacy of multifunctional matrices in oral peptide delivery has been verified by various in vivo studies that could pave the way for the development of commercially viable formulations. PMID:11763498
Ribosome evolution: Emergence of peptide synthesis machinery
Indian Academy of Sciences (India)
Koji Tamura
Proteins, the main players in current biological systems, are produced on ribosomes by sequential amide bond (peptide bond) formations between amino-acid-bearing tRNAs. The ribosome is an exquisite super-complex of RNA-proteins, containing more than 50 proteins and at least 3 kinds of RNAs. The combination of a variety of side chains of amino acids (typically 20 kinds with some exceptions) confers proteins with extraordinary structure and functions. The origin of peptide bond formation and the ribosome is crucial to the understanding of life itself. In this article, a possible evolutionary pathway to peptide bond formation machinery (proto-ribosome) will be discussed, with a special focus on the RNA minihelix (primordial form of modern tRNA) as a starting molecule. Combining the present data with recent experimental data, we can infer that the peptidyl transferase center (PTC) evolved from a primitive system in the RNA world comprising tRNA-like molecules formed by duplication of minihelix-like small RNA.
Implicit biology in peptide spectral libraries.
Askenazi, Manor; Linial, Michal
Mass spectral libraries are collections of mass spectra curated specifically to facilitate the identification of small molecules, metabolites, and short peptides. One of the most comprehensive peptide spectral libraries is curated by NIST and contains upward of half a million annotated spectra dominated by human and model organisms including budding yeast and mouse. While motivated primarily by the technological goal of increasing sensitivity and specificity in spectral identification, we have found that the NIST spectral library constitutes a surprisingly rich source of biological knowledge. In this Article, we show that data-mining of these published libraries while applying strict empirical thresholds yields many characteristics of protein biology. In particular, we demonstrate that the size and increasingly comprehensive nature of these libraries, generated from whole-proteome digests, enables inference from the presence but crucially also from the absence of spectra for individual peptides. We illustrate implicit biological trends that lead to significant absence of spectra accounted for by complex post-translational modifications and overlooked proteolytic sites. We conclude that many subtle biological signatures such as genetic variants, regulated proteolysis, and post-translational modifications are exposed through the systematic mining of spectral collections originally compiled as general-purpose, technology-oriented resources. PMID:22909014
An extensive library of surrogate peptides for all human proteins.
Mohammed, Yassene; Borchers, Christoph H
Selecting the most appropriate surrogate peptides to represent a target protein is a major component of experimental design in Multiple Reaction Monitoring (MRM). Our software PeptidePicker with its v-score remains distinctive in its approach of integrating information about the proteins, their tryptic peptides, and the suitability of these peptides for MRM that is available online in UniProtKB, NCBI's dbSNP, ExPASy, PeptideAtlas, PRIDE, and GPMDB. The scoring algorithm reflects our "best knowledge" for selecting candidate peptides for MRM, based on the uniqueness of the peptide in the targeted proteome, its physiochemical properties, and whether it has previously been observed. Here we present an updated approach where we have already compiled a list of all possible surrogate peptides of the human proteome. Using our stringent selection criteria, the list includes 165k suitable MRM peptides covering 17k proteins of the human reviewed proteins in UniProtKB. Compared to average of 2-4min per protein for retrieving and integrating the information, the precompiled list includes all peptides available instantly. This allows a more cohesive and faster design of a multiplexed MRM experiment and provides insights into evidence for a protein's existence. We will keep this list up-to-date as proteomics data repositories continue to grow. This article is part of a Special Issue entitled: Computational Proteomics. PMID:26232110
Directory of Open Access Journals (Sweden)
Full Text Available Extensive use of classical antibiotics has led to the growing emergence of many resistant strains of pathogenic bacteria. Evidence has suggested that cationic antimicrobial peptides (AMP's are of greatest potential to represent a new class of antibiotics. These peptides have a good scope in current antibiotic research. During the past two decades several AMPs have been isolated from a wide variety of animals (both vertebrates and invertebrates, and plants as well as from bacteria and fungi. These are relatively small (<10kDa, cationic and amphipathic peptides of variable length, sequence and structure. These peptides exhibit broad-spectrum activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, protozoa, yeast, fungi and viruses. Most of these peptides are believed to act by disrupting the plasma membrane leading to the lysis of the cell. Antimicrobial peptides encompass a wide variety of structural motifs such as α -helical peptides, β -sheet peptides, looped peptides and extended peptides. Preparations enriched by a specific protein are rarely easily obtained from natural host cells. Hence, recombinant protein production is frequently the sole applicable procedure. Several fusion strategies have been developed for the expression and purification of small antimicrobial peptides (AMPs in recombinant bacterial expression systems which were produced by cloning. This article aims to review in brief the sources of antimicrobial peptides, diversity in structural features, mode of action, production strategies and insight into the current data on their antimicrobial activity followed by a brief comment on the peptides that have entered clinical trials.
Stability of diphenylalanine peptide nanotubes in solution
Andersen, Karsten Brandt; Castillo-Leon, Jaime; Hedström, Martin; Svendsen, Winnie Edith
Over the last couple of years, self-organizing nanotubes based on the dipeptide diphenylalanine have received much attention, mainly as possible building blocks for the next generation of biosensors and as drug delivery systems. One of the main reasons for this large interest is that these peptide nanotubes are believed to be very stable both thermally and chemically. Previously, the chemical and thermal stability of self-organizing structures has been investigated after the evaporation of the solvent. However, it was recently discovered that the stability of the structures differed significantly when the tubes were in solution. It has been shown that, in solution, the peptide nanotubes can easily be dissolved in several solvents including water. It is therefore of critical importance that the stability of the nanotubes in solution and not after solvent evaporation be investigated prior to applications in which the nanotube will be submerged in liquid. The present article reports results demonstrating the instability and suggests a possible approach to a stabilization procedure, which drastically improves the stability of the formed structures. The results presented herein provide new information regarding the stability of self-organizing diphenylalanine nanotubes in solution.Over the last couple of years, self-organizing nanotubes based on the dipeptide diphenylalanine have received much attention, mainly as possible building blocks for the next generation of biosensors and as drug delivery systems. One of the main reasons for this large interest is that these peptide nanotubes are believed to be very stable both thermally and chemically. Previously, the chemical and thermal stability of self-organizing structures has been investigated after the evaporation of the solvent. However, it was recently discovered that the stability of the structures differed significantly when the tubes were in solution. It has been shown that, in solution, the peptide nanotubes can
Light-Switchable Peptides with a Hemithioindigo Unit: Peptide Design, Photochromism, and Optical Spectroscopy.
Kitzig, S; Thilemann, M; Cordes, T; Rück-Braun, Karola
This Minireview focuses on the hemithioindigo photoswitch and its use for the reversible control of three-dimensional peptide structure and related biological functions. Both the general design aspects and biophysical properties of various hemithioindigo-based chromopeptides are summarized. Hemithioindigo undergoes reversible Z→E photoisomerization after absorption of visible light. The unique ultrafast switching mechanism of hemithioindigo combines picosecond isomerization kinetics with strong double-bond torsion after light absorption, making it the ideal tool for instantaneous modulation of biological structure. Various inhibitors and model peptides based on hemithioindigo are described that can directly regulate biological signaling or allow the fastest events in peptide folding to be studied. Finally, a diverse range of chromopeptides with photoswitchable β-hairpin structures based on azobenzenes, stilbenes, and hemithioindigo are compared to emphasize the unique properties of hemithioindigo. PMID:26789782
Peptide and non-peptide opioid-induced hyperthermia in rabbits
Kandasamy, S. B.; Williams, B. A.
The intracerebroventricular administration of prototype nonpeptide opioid receptor (mu, kappa, and sigma) agonists, morphine, ketocyclazocine, and N-allyl-normetazocine was found to induce hyperthermia in rabbits. The similar administration of peptide opioids like beta-endorphin (BE), methionine-enkephalin (ME), and its synthetic analogue D-ala2-methionine-enkephalinamide (DAME) was also found to cause hyperthermia. Results indicate that only the liver-like transport system is important to the ventricular inactivation of BE and DAME. Prostaglandins and norepinephrine were determined not to be involved in peptide and nonpeptide opioid-induced hyperthermia. In addition, cAMP was not required since a phosphodiesterase inhibitor, theophylline, did not accentuate the hyperthermia due to peptide and nonpeptide opioids. Naloxone-sensitive receptors were found to be involved in the induction of hyperthermia by morphine, BE, ME, and DAME since naloxone attenuated them. However, the hyperthermic response to ketocyclazocine and N-allyl-normetazocine was not antagonized by naloxone.
Correlations between fasting plasma C-peptide, glucagon-stimulated plasma C-peptide, and urinary C-peptide in insulin-treated diabetics
DEFF Research Database (Denmark)
Gjessing, H J; Matzen, L E; Frøland, A;
This study correlated fasting plasma C-peptide (CP), plasma CP 6 min after stimulation with 1 mg glucagon i.v., and the mean of three 24-h urinary excretions of C-peptide (UCP)/creatinine in 132 insulin-treated diabetics. Patients were divided into three groups: group 1, stimulated CP less than 0...
Fasting plasma C-peptide, glucagon stimulated plasma C-peptide, and urinary C-peptide in relation to clinical type of diabetes
DEFF Research Database (Denmark)
Gjessing, H J; Matzen, L E; Faber, O K;
Many patients with Type 2 (non-insulin-dependent) diabetes mellitus are treated with insulin in order to control hyperglycaemia. We studied fasting plasma C-peptide, glucagon stimulated plasma C-peptide, and 24 h urinary C-peptide in relation to clinical type of diabetes in 132 insulin treated...... fasting plasma C-peptide value less than 0.20 nmol/l, a glucagon stimulated plasma C-peptide value less than 0.32 nmol/l, and a urinary C-peptide value less than 3.1 nmol/l, or less than 0.54 nmol/mmol creatinine/24 h, or less than 5.4 nmol/24 h mainly were Type 1 diabetic patients; while patients with C-peptide......) weight below 110% of ideal weight of the same age and sex. Eighty patients were classified as Type 1 and 52 as Type 2 diabetic subjects. A second classification of patients into 6 C-peptide classes was then performed. Class I consisted of patients without islet B-cell function. Class II-VI had preserved...
Review: Formation of Peptide Radical Ions Through Dissociative Electron Transfer in Ternary Metal-Ligand-Peptide Complexes
International Nuclear Information System (INIS)
The formation and fragmentation of odd-electron ions of peptides and proteins is of interest to applications in biological mass spectrometry. Gas-phase redox chemistry occurring during collision-induced dissociation of ternary metal-ligand-peptide complexes enables the formation of a variety of peptide radicals including the canonical radical cations, M+#smbullet#, radical dications, (M+H)2+#smbullet#, radical anions, (M-2H)-#smbullet#. In addition, odd-electron peptide ions with well-defined initial location of the radical site are produced through side chain losses from the radical ions. Subsequent fragmentation of these species provides information on the role of charge and the location of the radical site on the competition between radical-induced and proton-driven fragmentation of odd-electron peptide ions. This account summarizes current understanding of the factors that control the efficiency of the intramolecular electron transfer (ET) in ternary metal-ligand-peptide complexes resulting in formation of odd-electron peptide ions. Specifically, we discuss the effect of the metal center, the ligand and the peptide structure on the competition between the ET, proton transfer (PT), and loss of neutral peptide and neutral peptide fragments from the complex. Fundamental studies of the structures, stabilities, and the energetics and dynamics of fragmentation of such complexes are also important for detailed molecular-level understanding of photosynthesis and respiration in biological systems.
Mixed α/β-Peptides as a Class of Short Amphipathic Peptide Hydrogelators with Enhanced Proteolytic Stability.
Mangelschots, Jeroen; Bibian, Mathieu; Gardiner, James; Waddington, Lynne; Van Wanseele, Yannick; Van Eeckhaut, Ann; Acevedo, Maria M Diaz; Van Mele, Bruno; Madder, Annemieke; Hoogenboom, Richard; Ballet, Steven
Peptide hydrogels are a highly promising class of materials for biomedical application, albeit facing many challenges with regard to stability and tunability. Here, we report a new class of amphipathic peptide hydrogelators, namely mixed α/β-peptide hydrogelators. These mixed α/β-gelators possess good rheological properties (high storage moduli) and form transparent self-supporting gels with shear-thinning behavior. Infrared spectroscopy indicates the presence of β-sheets as the underlying secondary structure. Interestingly, self-assembled nanofibers of the mixed α/β-peptides display unique structural morphologies with alteration of the C-terminus (acid vs amide) playing a key role in the fiber formation and gelation properties of the resulting hydrogels. The incorporation of β3-homoamino acid residues within the mixed α/β-peptide gelators led to an increase in proteolytic stability of the peptides under nongelating conditions (in solution) as well as gelating conditions (as hydrogel). Under diluted conditions, degradation of mixed α/β-peptides in the presence of elastase was slowed down 120-fold compared to that of an α-peptide, thereby demonstrating beneficial enzymatic resistance for hydrogel applications in vivo. In addition, increased half-life values were obtained for the mixed α/β-peptides in human blood plasma, as compared to corresponding α-peptides. It was also found that the mixed α/β-peptides were amenable to injection via needles used for subcutaneous administrations. The preformed peptide gels could be sheared upon injection and were found to quickly reform to a state close to that of the original hydrogel. The shown properties of enhanced proteolytic stability and injectability hold great promise for the use of these novel mixed α/β-peptide hydrogels for applications in the areas of tissue engineering and drug delivery. PMID:26741458
Novel Zn2+-chelating peptides selected from a fimbria-displayed random peptide library
DEFF Research Database (Denmark)
Kjærgaard, Kristian; Schembri, Mark; Klemm, Per
The display of peptide sequences on the surface of bacteria is a technology that offers exciting applications in biotechnology and medical research. Type 1 fimbriae are surface organelles of Escherichia coli which mediate D-mannose-sensitive binding to different host surfaces by virtue of the Fim...... peptide sequences that conferred on recombinant cells the ability to bind Zn2+. By serial selection, sequences that exhibited various degrees of binding affinity and specificity toward Zn2+ were enriched. None of the isolated sequences showed similarity to known Zn2+-binding proteins, indicating that...
Advances in Fmoc solid-phase peptide synthesis.
Behrendt, Raymond; White, Peter; Offer, John
Today, Fmoc SPPS is the method of choice for peptide synthesis. Very-high-quality Fmoc building blocks are available at low cost because of the economies of scale arising from current multiton production of therapeutic peptides by Fmoc SPPS. Many modified derivatives are commercially available as Fmoc building blocks, making synthetic access to a broad range of peptide derivatives straightforward. The number of synthetic peptides entering clinical trials has grown continuously over the last decade, and recent advances in the Fmoc SPPS technology are a response to the growing demand from medicinal chemistry and pharmacology. Improvements are being continually reported for peptide quality, synthesis time and novel synthetic targets. Topical peptide research has contributed to a continuous improvement and expansion of Fmoc SPPS applications. PMID:26785684
Characterization of Selective Antibacterial Peptides by Polarity Index
Directory of Open Access Journals (Sweden)
C. Polanco
Full Text Available In the recent decades, antibacterial peptides have occupied a strategic position for pharmaceutical drug applications and became subject of intense research activities since they are used to strengthen the immune system of all living organisms by protecting them from pathogenic bacteria. This work proposes a simple and easy statistical/computational method through a peptide polarity index measure by which an antibacterial peptide subgroup can be efficiently identified, that is, characterized by a high toxicity to bacterial membranes but presents a low toxicity to mammal cells. These peptides also have the feature not to adopt to an alpha-helicoidal structure in aqueous solution. The double-blind test carried out to the whole Antimicrobial Peptide Database (November 2011 showed an accuracy of 90% applying the polarity index method for the identification of such antibacterial peptide groups.
Optimization of reversed-phase chromatography methods for peptide analytics.
Khalaf, Rushd; Baur, Daniel; Pfister, David
The analytical description and quantification of peptide solutions is an essential part in the quality control of peptide production processes and in peptide mapping techniques. Traditionally, an important tool is analytical reversed phase liquid chromatography. In this work, we develop a model-based tool to find optimal analytical conditions in a clear, efficient and robust manner. The model, based on the Van't Hoff equation, the linear solvent strength correlation, and an analytical solution of the mass balance on a chromatographic column describing peptide retention in gradient conditions is used to optimize the analytical scale separation between components in a peptide mixture. The proposed tool is then applied in the design of analytical reversed phase liquid chromatography methods of five different peptide mixtures. PMID:26620597
Proinflammatory Effects of C-Peptide in Different Tissues
Directory of Open Access Journals (Sweden)
Dusica Vasic
Full Text Available Atherosclerosis is well known as an inflammatory disease that can lead to clinical complications such as heart attack or stroke. C-peptide as a cleavage product of proinsulin is in the last few decades known as an active peptide with a number of different effects on microvascular and macrovascular complications in type 2 diabetic patients. Patients with insulin resistance and early type 2 diabetes show elevated levels of C-peptide in blood. Several last findings demonstrated deposition of C-peptide in the vessel wall in ApoE-deficient mice and induction of local inflammation. Besides that, C-peptide has proliferative effects on human mesangial cells. This review discusses recently published proinflammatory effects of C-peptide in different tissues.
Oxidative stress can alter the antigenicity of immunodominant peptides
DEFF Research Database (Denmark)
Weiskopf, Daniela; Schwanninger, Angelika; Weinberger, Birgit; Almanzar, Giovanni; Parson, Walther; Buus, Søren; Lindner, Herbert; Grubeck-Loebenstein, Beatrix
APCs operate frequently under oxidative stress induced by aging, tissue damage, pathogens, or inflammatory responses. Phagocytic cells produce peroxides and free-radical species that facilitate pathogen clearance and can in the case of APCs, also lead to oxidative modifications of antigenic...... proteins and peptides. Little information is available presently about the consequences of such modifications on the immune response. To model oxidative modification of an immunodominant antigenic peptide, we oxidized the methionine residue of the human CMV pp65(495-503) (NLVPMVATV) peptide. Such...... modifications of an antigenic peptide can affect MHC binding or TCR recognition. Using binding and dissociation assays, we demonstrate that oxidative modification of the CMVpp65(495-503) peptide leads to a decreased binding of the pMHC complex to the TCR, whereas binding of the peptide to the MHC class I...
Survey of small antifungal peptides with chemotherapeutic potential.
Desbois, Andrew P; Tschörner, David; Coote, Peter J
Many cationic peptides with antimicrobial properties have been isolated from bacteria, fungi, plants, and animals. These peptides vary in molecular size, potency and spectra of activities. This report surveyed the literature to highlight the peptides that have antifungal activity and greatest potential for development as new therapeutic agents. Thus, to be included in the evaluation, each peptide had to fulfil the following criteria: (i) potent antifungal activity, (ii) no, or minimal, mammalian cell toxicity, (iii) of ≤25 amino acids in length, which minimises the costs of synthesis, reduces immunogenicity and enhances bioavailability and stability in vivo, (iv) minimal post-translational modifications (also reduces the production costs). The ~80 peptides that satisfied these criteria are discussed with respect to their structures, mechanisms of antimicrobial action and in vitro and in vivo toxicities. Certainly, some of these small peptides warrant further study and have potential for future exploitation as new antifungal agents. PMID:21470150
C-type natriuretic-derived peptides as biomarkers in human disease
DEFF Research Database (Denmark)
Lippert, Solvej Kølvraa; Goetze, Jens Peter
and extracellular fluid volume. Atrial natriuretic peptide and B-type natriuretic peptide have gained considerable diagnostic interest as biomarkers in cardiovascular disease. By contrast, C-type natriuretic peptide has not yet been ascribed a role in human diagnostics. This perspective aims at......The natriuretic peptide system comprises three structurally related peptides: atrial natriuretic peptide, B-type natriuretic peptide and C-type natriuretic peptide. In circulation, they play an important endocrine role in the regulation of cardiovascular homeostasis by maintaining blood pressure...... recapitulating the present biochemical and clinical issues concerning C-type natriuretic peptide measurement in plasma as a potential biomarker....
Development of New Tools for the Synthesis of "Difficult Peptides"
Paradís Bas, Marta
Tesi realitzada a l'Institut de Recerca Biomèdica de Barcelona (IRBB) The known as "difficult peptides", as well as those sequences that aggregate in solution, are some of those molecules with high applicability as nanomaterials or even in medicine field. This thesis has addressed to overcome the synthetic, as well as, the peptide manipulation in solution drawbacks associated to this kind of peptides. The strategies proposed and evaluated in the present work have been divided in three chap...
Targeting cyclin-dependent kinases in Drosophila with peptide aptamers
Kolonin, Mikhail G.; Finley, Russell L.
Two-hybrid technology provides a simple way to isolate small peptide aptamers that specifically recognize and strongly bind to a protein of interest. These aptamers have the potential to dominantly interfere with specific activities of their target proteins and, therefore, could be used as in vivo inhibitors. Here we explore the ability to use peptide aptamers as in vivo inhibitors by expressing aptamers directed against cell cycle regulators in Drosophila. We expressed two peptide aptamers, ...
Lasso peptide, a highly stable structure and designable multifunctional backbone.
Zhao, Ning; Pan, Yongxu; Cheng, Zhen; Liu, Hongguang
Lasso peptide belongs to a new class of natural product with highly compact and stable structure. It has varieties of biological activities, among which the most important one is its antibacterial efficacy. Novel lasso peptides have been constantly discovered and analyzed by advanced techniques, and the biosynthesis or even chemical synthesis of lasso peptide has been studied after learning its constituent amino acids and maturation process. Structural identification of lasso peptide provides information for elucidating the mechanisms of its antibacterial activity and basis for further modifications. Ring of lasso peptide is the key to both its highly compact and stable structure and its intrinsic antibacterial property. The loop has been considered as suitable modification region of lasso peptide, such as V11-S18 of MccJ25 being modifiable without disrupting the lasso structure in biosynthesis. The tail is the immunity protein that can export lasso peptide out of its produced strain and serve as a self-protection mechanism at the same time. Most of currently known lasso peptides are non-pathogenic, which implies that the modified lasso peptides are promising candidates for medical applications. Arginine, glycine, and aspartic acid as a ligands of cancer-specific receptor have been grafted to the loop of lasso peptide without losing its bioactivity, and many other targets are expected to be used for lasso peptide modification. Multi-molecular modification and large-scale production need to be studied and solved in future for designing and using multifunctional lasso peptide based on its extraordinary stable structure. PMID:27074719
Photodissociation of Non-Covalent Peptide-Crown Ether Complexes
Wilson, Jeffrey J.; Kirkovits, Gregory J.; Sessler, Jonathan L.; Brodbelt, Jennifer S.
Highly chromogenic 18-crown-6-dipyrrolylquinoxaline coordinates primary amines of peptides, forming non-covalent complexes that can be transferred to the gas phase by electrospray ionization. The appended chromogenic crown ether facilitates efficient energy transfer to the peptide upon ultraviolet irradiation in the gas phase, resulting in diagnostic peptide fragmentation. Collisional activated dissociation (CAD) and infrared multiphoton dissociation (IRMPD) of these non-covalent complexes re...
CLE Peptide Signaling and Crosstalk with Phytohormones and Environmental Stimuli
Wang, Guodong; Zhang, Guohua; Wu, Mengyao
The CLE (CLAVATA3/Endosperm surrounding region-related) peptide family is one of the best-studied secreted peptide families in plants. Accumulated data have revealed that CLE genes play vital roles on stem cell homeostasis in different types of meristems. Additionally, CLE genes have been found to perform various biological roles in plant growth and development, and in response to environmental stimuli. With recent advances on our understanding of CLE peptide function, it is showing that the ...
Urinary Peptide Levels in Patients with Chronic Renal Failure
Mungli Prakash; Phani, Nagaraj M; Kavya R; Supriya M
Introduction: Peptide levels in urine are found to be decreased in renal failure. In the current study urinary peptide levels were determined in chronic renal failure (CRF) patients. Method: 86 CRF patients and 80 healthy controls were selected for the study. Urinary proteins and peptide levels were determined by spectrophotometer based Lowry and Bradford methods. Urinary creatinine levels were determined by clinical chemistry analyzer. Results: There was significant decrease in urinary pepti...
An Interplay between Electrostatic and Polar Interactions in Peptide Hydrogels
Joyner, Katherine; Taraban, Marc B; Feng, Yue; Yu, Y. Bruce
Inherent chemical programmability available in peptide-based hydrogels has allowed diversity in the development of these materials for use in biomedical applications. Within the 20 natural amino acids, a range of chemical moieties are present. Here we used a mixing-induced self-assembly of two oppositely charged peptide modules to form a peptide-based hydrogel. To investigate electrostatic and polar interactions on the hydrogel, we replace amino acids from the negatively charged acidic glutam...
Analysis of illegal peptide biopharmaceuticals frequently encountered by controlling agencies.
Vanhee, Celine; Janvier, Steven; Desmedt, Bart; Moens, Goedele; Deconinck, Eric; De Beer, Jacques O; Courselle, Patricia
Recent advances in genomics, recombinant expression technologies and peptide synthesis have led to an increased development of protein and peptide therapeutics. Unfortunately this goes hand in hand with a growing market of counterfeit and illegal biopharmaceuticals, including substances that are still under pre-clinical and clinical development. These counterfeit and illegal protein and peptide substances could imply severe health threats as has been demonstrated by numerous case reports. The Belgian Federal Agency for Medicines and Health Products (FAMHP) and customs are striving, together with their global counterparts, to curtail the trafficking and distributions of these substances. At their request, suspected protein and peptide preparations are analysed in our Official Medicines Control Laboratory (OMCL). It stands to reason that a general screening method would be beneficiary in the battle against counterfeit and illegal peptide drugs. In this paper we present such general screening method employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the identification of counterfeit and illegal injectable peptide preparations, extended with a subsequent quantification method using ultra-high performance liquid chromatography with diode array detection (UHPLC-DAD). The screening method, taking only 30 min, is able to selectively detect 25 different peptides and incorporates the proposed minimum of five identification points (IP) as has been recommended for sports drug testing applications. The group of peptides represent substances which have already been detected in illegal and counterfeit products seized by different European countries as well as some biopharmaceutical peptides which have not been confiscated yet by the controlling agencies, but are already being used according to the many internet users forums. Additionally, we also show that when applying the same LC gradient, it is also possible to quantify these peptides without the need for
Chemo-enzymatic peptide synthesis : bioprocess engineering aspects
Vossenberg, P.
Peptides, in particular oligopeptides, play an important role in the fields of health care, nutrition and cosmetics. Chemical synthesis is currently the most mature technique for the synthesis of peptides that range in length from 5 to 80 amino acids. Chemical synthesis is, however, expected to be more and more combined with enzyme-catalyzed synthesis, resulting in chemo-enzymatic approaches towards peptide synthesis. The racemization that hampers chemical synthesis can be prevented by...
Origination of the Protein Fold Repertoire from Oily Pluripotent Peptides
Mannige, Ranjan V.
While the repertoire of protein folds that exists today underlies most of life's capabilities, our mechanistic picture of protein fold origination is incomplete. This paper discusses a hypothetical mechanism for the emergence of the protein fold repertoire from highly dynamic and collapsed peptides, exemplified by peptides with high oil content or hydrophobicity. These peptides are called pluripotent to emphasize their capacity to evolve into numerous folds transiently available to them. As e...
Injectable polymer microspheres enhance immunogenicity of a contraceptive peptide vaccine
Cui, Chengji; Stevens, Vernon C.; Schwendeman, Steven P.
Advanced contraceptive peptide vaccines suffer from the unavailability of adjuvants capable of enhancing the antibody response with acceptable safety. We sought to overcome this limitation by employing two novel poly(lactic-co-glycolic acid) (PLGA) microsphere formulations to deliver a synthetic human chorionic gonadotropin (hCG) peptide antigen co-synthesized with a T-cell epitope from tetanus toxoid, C-TT2-CTP35: surface-conjugated immunogen to induce phagocytosis; and encapsulated peptide ...
Proinsulin C-peptide interferes with insulin fibril formation
Energy Technology Data Exchange (ETDEWEB)
Landreh, Michael [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm (Sweden); Stukenborg, Jan-Bernd [Department of Women' s and Children' s Health, Astrid Lindgren Children' s Hospital, Pediatric Endocrinology Unit, Karolinska Institutet and University Hospital, S-17176 Stockholm (Sweden); Willander, Hanna [KI-Alzheimer' s Disease Research Center, NVS Department, Karolinska Institutet, S-141 86 Stockholm (Sweden); Soeder, Olle [Department of Women' s and Children' s Health, Astrid Lindgren Children' s Hospital, Pediatric Endocrinology Unit, Karolinska Institutet and University Hospital, S-17176 Stockholm (Sweden); Johansson, Jan [KI-Alzheimer' s Disease Research Center, NVS Department, Karolinska Institutet, S-141 86 Stockholm (Sweden); Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, S-751 23 Uppsala (Sweden); Joernvall, Hans, E-mail: firstname.lastname@example.com [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm (Sweden)
Highlights: Black-Right-Pointing-Pointer Insulin and C-peptide can interact under insulin fibril forming conditions. Black-Right-Pointing-Pointer C-peptide is incorporated into insulin aggregates and alters aggregation lag time. Black-Right-Pointing-Pointer C-peptide changes insulin fibril morphology and affects backbone accessibility. Black-Right-Pointing-Pointer C-peptide may be a regulator of fibril formation by {beta}-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic {beta}-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.
Immunological half-life of porcine proinsulin C-peptide
International Nuclear Information System (INIS)
Immunological half-lifes of injected porcine C-peptide and insulin with RIA were studied and calculated as 9.8 and 8.0 minutes. Higher circulating levels of C-peptide as compared to insulin in normal young swines lead to speculation about a longer half-life of C-peptide. This hypothesis was verified in this study. Immunological half-lifes of porcine proinsulin and insulin in the pig were 20 and 6 minutes, respectively. (GSE)
Proinsulin C-peptide interferes with insulin fibril formation
International Nuclear Information System (INIS)
Highlights: ► Insulin and C-peptide can interact under insulin fibril forming conditions. ► C-peptide is incorporated into insulin aggregates and alters aggregation lag time. ► C-peptide changes insulin fibril morphology and affects backbone accessibility. ► C-peptide may be a regulator of fibril formation by β-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic β-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.
Nonlinear Optical Properties of Triphenylalanine-based Peptide Nanostructures
Kudryavtsev, A. V.; Mishina, E. D.; Sigov, A. S.
Nonlinear optical properties of peptide nanobelts and peptide nanospheres, the two types of self-assembled triphenylalanine-based peptide nanostructures, are studied. Nanobelts nonlinear susceptibility tensor components are evaluated, and nanobelts crystal structure and crystallographic orientation are defined on the basis of nonlinear optical mapping and polarization dependences of the second harmonic signal. The results obtained suggest that it is possible to use these materials as biologically compatible nonlinear optical converters.
Carrier peptide-mediated transepithelial permeation of biopharmaceuticals
DEFF Research Database (Denmark)
Kristensen, Mie; Nielsen, Hanne Mørck
-penetrating peptides (CPPs). Two approaches for the carrier peptide-mediated transepithelial permeation of biopharmaceuticals are generally explored: Co-administration1 or covalent conjugation2. Co-administration is often the method of choice due to e.g. ease in sample preparation and flexibility in adjustment of the......-34)) and the widely studied CPP penetratin were employed as therapeutic cargo and carrier peptide, respectively....
Incorporation of peptides in phospholipid aggregates using ultrasound
Silva, Raquel; Little, Collin; Ferreira, Helena; Paulo, Artur Cavaco
This study presents the highlights of ultrasonic effects on peptides incorporated on phospholipid aggregates (liposomes). These liposomes or vesicles are known as transport agents in skin drug delivery and for hair treatment. They might be a good model to deliver larger peptides into hair to restore fibre strength after hair coloration, modelling, permanent wave and/or straightening. The preparation of liposomes 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC) with peptides (LLLLK LLLLK LL...
IPG strip-based peptide fractionation for shotgun proteomics
Eravci, M.; Sommer, C; Selbach, M
Efficient fractionation of peptides is an essential prerequisite for comprehensive analysis of complex protein mixtures by shotgun mass spectrometry. The separation of peptides by isoelectric focusing is particularly attractive due to its orthogonality to reverse-phase HPLC. Here, we present a protocol for in-gel peptide isoelectric focusing using immobilized pH gradient strips. The method shows high resolving power for up to 1 mg of sample and is highly reproducible.
TOPICAL REVIEW: Nonlinear two-dimensional vibrational spectroscopy of peptides
Woutersen, Sander; Hamm, Peter
In this overview, we discuss theoretical and experimental aspects of nonlinear two-dimensional infrared (2D-IR) spectroscopy. With this technique both peptide conformation and conformational flexibility can be probed. The quantitative relation between the experimental 2D-IR spectrum and the peptide conformation is discussed, and examples of how the conformation of a peptide and the timescale of its fluctuations are derived from its (time-resolved) 2D spectrum are presented.
Protein and lipid interactions of mammalian antibacterial peptides
Wang, Yuqin
Gene-encoded antibacterial peptides are multifunctional effector molecules and play an important role in host innate immunity. Upon stimulation, the mature active peptides are released from inactive precursors. Cathelicidins constitute a family of antibacterial peptides, which share a conserved N-terminal cathelin-like region followed by a variable C-terminal antibacterial domain. In addition to its antibacterial activity, LL-37, the only cathelicidin found in human, is ...
Interpretation of tandem mass spectra obtained from cyclic nonribosomal peptides.
Liu, Wei-Ting; Ng, Julio; Meluzzi, Dario; Bandeira, Nuno; Gutierrez, Marcelino; Simmons, Thomas L; Schultz, Andrew W; Linington, Roger G; Moore, Bradley S; Gerwick, William H; Pevzner, Pavel A; Dorrestein, Pieter C
Natural and non-natural cyclic peptides are a crucial component in drug discovery programs because of their considerable pharmaceutical properties. Cyclosporin, microcystins, and nodularins are all notable pharmacologically important cyclic peptides. Because these biologically active peptides are often biosynthesized nonribosomally, they often contain nonstandard amino acids, thus increasing the complexity of the resulting tandem mass spectrometry data. In addition, because of the cyclic nature, the fragmentation patterns of many of these peptides showed much higher complexity when compared to related counterparts. Therefore, at the present time it is still difficult to annotate cyclic peptides MS/MS spectra. In this current work, an annotation program was developed for the annotation and characterization of tandem mass spectra obtained from cyclic peptides. This program, which we call MS-CPA is available as a web tool (http://lol.ucsd.edu/ms-cpa_v1/Input.py). Using this program, we have successfully annotated the sequence of representative cyclic peptides, such as seglitide, tyrothricin, desmethoxymajusculamide C, dudawalamide A, and cyclomarins, in a rapid manner and also were able to provide the first-pass structure evidence of a newly discovered natural product based on predicted sequence. This compound is not available in sufficient quantities for structural elucidation by other means such as NMR. In addition to the development of this cyclic annotation program, it was observed that some cyclic peptides fragmented in unexpected ways resulting in the scrambling of sequences. In summary, MS-CPA not only provides a platform for rapid confirmation and annotation of tandem mass spectrometry data obtained with cyclic peptides but also enables quantitative analysis of the ion intensities. This program facilitates cyclic peptide analysis, sequencing, and also acts as a useful tool to investigate the uncommon fragmentation phenomena of cyclic peptides and aids the
Paramagnetic relaxation enhancements in NMR peptide-membrane interaction studies
International Nuclear Information System (INIS)
Small membrane-bound proteins or peptides are involved in numerous essential biological processes, like cellular recognition, signaling, channel formation, and cytolysis. The secondary structure, orientation, mode of interaction and dynamics of these peptides can be as varied as their functions. Their localization in the membrane, the immersion depth, and their binding mode are factors critical to the function of these peptides. The atomic 3D solution structure of peptides bound to micelles can be determined by NMR spectroscopy. However, by employing paramagnetic relaxation enhancements (PREs) information on the complete topology of peptide bound to a micelle can be obtained. The antimicrobial peptide maximin H6, fst, a bacterial toxin, and the human peptide hormone ghrelin served as membrane-bound model peptides of similar sizes but strongly differing amino acid sequences. Their structures and binding behavior were determined and compared.The measured PREs provided suitable data for determining and distinguishing the different topologies of the investigated peptides bound to micelles. Maximin H6 and fst fold into α-helices upon insertion into a membrane, whereas the unstructured ghrelin is freely mobile in solution and interacts only via a covalently bound octanoyl group with the lipids. Maximin H6 is oriented parallel to the membrane surface, enabling the peptide to aggregate at the membrane water interface. Fst binds in transmembrane orientation with a protruding intrinsically disordered region near the C-terminus. Aside from determining the orientation of the bound peptides from the PREs, the moieties critical for membrane binding could be mapped in ghrelin. If suitable relaxation-edited spectra are acquired, the complete orientation and immersion depth of a peptide bound to a micelle can readily be obtained. (author)
Role of Host-Defence Peptides in Eye Diseases
Kolar, Satya S.; McDermott, Alison M.
The eye and its associated tissues including the lacrimal system and lids have evolved several defence mechanisms to prevent microbial invasion. Included among this armory are several host-defence peptides. These multifunctional molecules are being studied not only for their endogenous antimicrobial properties but also for their potential therapeutic effects. Here the current knowledge of host-defence peptide expression in the eye will be summarized. The role of these peptides in eye disease ...
Isolation and characterization of regulatory peptides and bioactive compounds
Norberg, Åke
Isolation of peptides and other bioactive compounds is an important and often necessary step to get the total information about their structures. This is demonstrated by a number of different characterizations in this thesis. Bioactive peptides and small organic molecules can act as signaling substances and messengers in multicellular organisms and are fundamental to higher forms of life. The following bioactive peptides and compounds were studied. 1) Different assays ca...
Discriminating self from nonself with short peptides from large proteomes
DEFF Research Database (Denmark)
Burrouhgs, N.J.; Boer, R.J.; Kesmir, Can
information. Our results show that this is not the case because the HLA molecules are fairly specific. Removing the two anchor residues from each presented peptide, we find that the self:nonself overlap of these exposed 7-mers resembles that of 9-mers. Summarizing, the 9-mers used in MHC class I presentation...... tend to carry sufficient information to detect nonself peptides amongst self peptides....
Competitive binding of antagonistic peptides fine-tunes stomatal patterning
Lee, Jin Suk; Hnilova, Marketa; Maes, Michal; Lin, Ya-Chen Lisa; Putarjunan, Aarthi; Han, Soon-Ki; Avila, Julian; U.Torii, Keiko
During development, cells interpret complex, often conflicting signals to make optimal decisions. Plant stomata, the cellular interface between a plant and the atmosphere, develop according to positional cues including a family of secreted peptides, EPIDERMAL PATTERNING FACTORS (EPFs). How these signaling peptides orchestrate pattern formation at a molecular level remains unclear. Here we report that Stomagen/EPF-LIKE9 peptide, which promotes stomatal development, requires ERECTA (ER)-family ...
In Silico Approach for Predicting Toxicity of Peptides and Proteins
Gupta, Sudheer; Kapoor, Pallavi; Chaudhary, Kumardeep; Gautam, Ankur; Kumar, Rahul; . .; Gajendra P. S. Raghava
Background Over the past few decades, scientific research has been focused on developing peptide/protein-based therapies to treat various diseases. With the several advantages over small molecules, including high specificity, high penetration, ease of manufacturing, peptides have emerged as promising therapeutic molecules against many diseases. However, one of the bottlenecks in peptide/protein-based therapy is their toxicity. Therefore, in the present study, we developed in silico models for...
Peptide immobilized on gold particles enhances cell growth
Gong, Jiansheng; Ito, Yoshihiro
A multivalent ligand of thrombopoietin (TPO) was prepared by immobilization of mimetic peptides on gold particles. An effective peptide ligand containing cysteine was designed to enhance the growth of TPO-sensitive cells. The peptide was then immobilized on gold particles by self assembly. The multivalent ligand enhanced the growth of TPO-dependent cells and its activity was more than that of the monovalent ligand.
Bioactive Peptides from Muscle Sources: Meat and Fish
Directory of Open Access Journals (Sweden)
Catherine Stanton
Full Text Available Bioactive peptides have been identified in a range of foods, including plant, milk and muscle, e.g., beef, chicken, pork and fish muscle proteins. Bioactive peptides from food proteins offer major potential for incorporation into functional foods and nutraceuticals. The aim of this paper is to present an outline of the bioactive peptides identified in the muscle protein of meat to date, with a focus on muscle protein from domestic animals and fish. The majority of research on bioactives from meat sources has focused on angiotensin-1-converting enzyme (ACE inhibitory and antioxidant peptides.
Method for predicting peptide detection in mass spectrometry
Kangas, Lars [West Richland, WA; Smith, Richard D [Richland, WA; Petritis, Konstantinos [Richland, WA
A method of predicting whether a peptide present in a biological sample will be detected by analysis with a mass spectrometer. The method uses at least one mass spectrometer to perform repeated analysis of a sample containing peptides from proteins with known amino acids. The method then generates a data set of peptides identified as contained within the sample by the repeated analysis. The method then calculates the probability that a specific peptide in the data set was detected in the repeated analysis. The method then creates a plurality of vectors, where each vector has a plurality of dimensions, and each dimension represents a property of one or more of the amino acids present in each peptide and adjacent peptides in the data set. Using these vectors, the method then generates an algorithm from the plurality of vectors and the calculated probabilities that specific peptides in the data set were detected in the repeated analysis. The algorithm is thus capable of calculating the probability that a hypothetical peptide represented as a vector will be detected by a mass spectrometry based proteomic platform, given that the peptide is present in a sample introduced into a mass spectrometer.
Design of stable antimicrobial peptides through hydrocarbon stapling
Czech Academy of Sciences Publication Activity Database
Chapuis, Hubert Jean; Slaninová, Jiřina; Monincová, Lenka; Bednárová, Lucie; Čeřovský, Václav
Praha: Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 19-21. (Collection Symposium Series. 13). ISBN 978-80-86241-44-9. [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] R&D Projects: GA ČR GA203/08/0536 Institutional research plan: CEZ:AV0Z40550506 Keywords : amphipathic alpha-helices * antimicrobial peptides * peptide synthesis * ring closing metathesis ( RCM ) * peptide stapling Subject RIV: CC - Organic Chemistry
Ndinguri, Margaret W.; Solipuram, Rajasree; Gambrell, Robert P.; Aggarwal, Sita; Hansel, William; Hammer, Robert P.
Besides various side effects caused by platinum anticancer drugs, they are not efficiently absorbed by the tumor cells. Two Pt-peptide conjugates; cyclic mPeg-CNGRC-Pt (7) and cyclic mPeg-CNGRC-Pten (8) bearing the Asn-Gly-Arg (NGR) targeting sequence, a malonoyl linker and low molecular weight miniPEG groups have been synthesized. The platinum ligand was attached to the peptide via the carboxylic end of the malonate group at the end of the peptide. The pegylated peptide is non toxic and high...
Developing a Dissociative Nanocontainer for Peptide Drug Delivery
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Patrick Kelly
Full Text Available The potency, selectivity, and decreased side effects of bioactive peptides have propelled these agents to the forefront of pharmacological research. Peptides are especially promising for the treatment of neurological disorders and pain. However, delivery of peptide therapeutics often requires invasive techniques, which is a major obstacle to their widespread application. We have developed a tailored peptide drug delivery system in which the viral capsid of P22 bacteriophage is modified to serve as a tunable nanocontainer for the packaging and controlled release of bioactive peptides. Recent efforts have demonstrated that P22 nanocontainers can effectively encapsulate analgesic peptides and translocate them across blood-brain-barrier (BBB models. However, release of encapsulated peptides at their target site remains a challenge. Here a Ring Opening Metathesis Polymerization (ROMP reaction is applied to trigger P22 nanocontainer disassembly under physiological conditions. Specifically, the ROMP substrate norbornene (5-Norbornene-2-carboxylic acid is conjugated to the exterior of a loaded P22 nanocontainer and Grubbs II Catalyst is used to trigger the polymerization reaction leading to nanocontainer disassembly. Our results demonstrate initial attempts to characterize the ROMP-triggered release of cargo peptides from P22 nanocontainers. This work provides proof-of-concept for the construction of a triggerable peptide drug delivery system using viral nanocontainers.
Impact of multivalent charge presentation on peptide-nanoparticle aggregation.
Schöne, Daniel; Schade, Boris; Böttcher, Christoph; Koksch, Beate
Strategies to achieve controlled nanoparticle aggregation have gained much interest, due to the versatility of such systems and their applications in materials science and medicine. In this article we demonstrate that coiled-coil peptide-induced aggregation based on electrostatic interactions is highly sensitive to the length of the peptide as well as the number of presented charges. The quaternary structure of the peptide was found to play an important role in aggregation kinetics. Furthermore, we show that the presence of peptide fibers leads to well-defined nanoparticle assembly on the surface of these macrostructures. PMID:26124881
Perspective of Use of Antiviral Peptides against Influenza Virus.
Skalickova, Sylvie; Heger, Zbynek; Krejcova, Ludmila; Pekarik, Vladimir; Bastl, Karel; Janda, Jozef; Kostolansky, Frantisek; Vareckova, Eva; Zitka, Ondrej; Adam, Vojtech; Kizek, Rene
The threat of a worldwide influenza pandemic has greatly increased over the past decade with the emergence of highly virulent avian influenza strains. The increased frequency of drug-resistant influenza strains against currently available antiviral drugs requires urgent development of new strategies for antiviral therapy, too. The research in the field of therapeutic peptides began to develop extensively in the second half of the 20(th) century. Since then, the mechanisms of action for several peptides and their antiviral prospect received large attention due to the global threat posed by viruses. Here, we discussed the therapeutic properties of peptides used in influenza treatment. Peptides with antiviral activity against influenza can be divided into three main groups. First, entry blocker peptides such as a Flupep that interact with influenza hemagglutinin, block its binding to host cells and prevent viral fusion. Second, several peptides display virucidal activity, disrupting viral envelopes, e.g., Melittin. Finally, a third set of peptides interacts with the viral polymerase complex and act as viral replication inhibitors such as PB1 derived peptides. Here, we present a review of the current literature describing the antiviral activity, mechanism and future therapeutic potential of these influenza antiviral peptides. PMID:26492266
Perspective of Use of Antiviral Peptides against Influenza Virus
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Sylvie Skalickova
Full Text Available The threat of a worldwide influenza pandemic has greatly increased over the past decade with the emergence of highly virulent avian influenza strains. The increased frequency of drug-resistant influenza strains against currently available antiviral drugs requires urgent development of new strategies for antiviral therapy, too. The research in the field of therapeutic peptides began to develop extensively in the second half of the 20th century. Since then, the mechanisms of action for several peptides and their antiviral prospect received large attention due to the global threat posed by viruses. Here, we discussed the therapeutic properties of peptides used in influenza treatment. Peptides with antiviral activity against influenza can be divided into three main groups. First, entry blocker peptides such as a Flupep that interact with influenza hemagglutinin, block its binding to host cells and prevent viral fusion. Second, several peptides display virucidal activity, disrupting viral envelopes, e.g., Melittin. Finally, a third set of peptides interacts with the viral polymerase complex and act as viral replication inhibitors such as PB1 derived peptides. Here, we present a review of the current literature describing the antiviral activity, mechanism and future therapeutic potential of these influenza antiviral peptides.
Bioinspired peptide nanotubes: Deposition technology and physical properties
International Nuclear Information System (INIS)
Proteins and peptides have the intrinsic ability to self-assemble into elongated solid nanofibrils, which give rise to amyloid progressive neurodegenerative diseases (Alzheimer's, Parkinson, etc.). It has been found that of the core recognition motif of Aβ peptide is the diphenylalanine element. The diphenylalanine peptide can self-assemble into well-ordered peptide nanotubes (PNT). In this paper we report on our newly developed process-vapor deposition of PNT and 'bottom-up' nanotechnological techniques of PNT patterning. Study of several physical properties of PNT such as optical and electrochemical are presented. The results may lead to the development of a new generation of PNT-based bioinspired functional nanodevices.
Analytical model of peptide mass cluster centres with applications
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Lehrach Hans
Full Text Available Abstract Background The elemental composition of peptides results in formation of distinct, equidistantly spaced clusters across the mass range. The property of peptide mass clustering is used to calibrate peptide mass lists, to identify and remove non-peptide peaks and for data reduction. Results We developed an analytical model of the peptide mass cluster centres. Inputs to the model included, the amino acid frequencies in the sequence database, the average length of the proteins in the database, the cleavage specificity of the proteolytic enzyme used and the cleavage probability. We examined the accuracy of our model by comparing it with the model based on an in silico sequence database digest. To identify the crucial parameters we analysed how the cluster centre location depends on the inputs. The distance to the nearest cluster was used to calibrate mass spectrometric peptide peak-lists and to identify non-peptide peaks. Conclusion The model introduced here enables us to predict the location of the peptide mass cluster centres. It explains how the location of the cluster centres depends on the input parameters. Fast and efficient calibration and filtering of non-peptide peaks is achieved by a distance measure suggested by Wool and Smilansky.
PeptideMine - A webserver for the design of peptides for protein-peptide binding studies derived from protein-protein interactomes
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Gopal Balasubramanian
Full Text Available Abstract Background Signal transduction events often involve transient, yet specific, interactions between structurally conserved protein domains and polypeptide sequences in target proteins. The identification and validation of these associating domains is crucial to understand signal transduction pathways that modulate different cellular or developmental processes. Bioinformatics strategies to extract and integrate information from diverse sources have been shown to facilitate the experimental design to understand complex biological events. These methods, primarily based on information from high-throughput experiments, have also led to the identification of new connections thus providing hypothetical models for cellular events. Such models, in turn, provide a framework for directing experimental efforts for validating the predicted molecular rationale for complex cellular processes. In this context, it is envisaged that the rational design of peptides for protein-peptide binding studies could substantially facilitate the experimental strategies to evaluate a predicted interaction. This rational design procedure involves the integration of protein-protein interaction data, gene ontology, physico-chemical calculations, domain-domain interaction data and information on functional sites or critical residues. Results Here we describe an integrated approach called "PeptideMine" for the identification of peptides based on specific functional patterns present in the sequence of an interacting protein. This approach based on sequence searches in the interacting sequence space has been developed into a webserver, which can be used for the identification and analysis of peptides, peptide homologues or functional patterns from the interacting sequence space of a protein. To further facilitate experimental validation, the PeptideMine webserver also provides a list of physico-chemical parameters corresponding to the peptide to determine the feasibility of
Peptide imprinted receptors for the determination of the small cell lung cancer associated biomarker progastrin releasing peptide
DEFF Research Database (Denmark)
Qader, A. A.; Urraca, J.; Torsetnes, S. B.;
prior to LCMS based quantification. Peptide imprinted polymers with the best affinity characteristics were first identified from a 96-polymer combinatorial library. The effects of functional monomers, crosslinker, porogen, and template on adsorption capacity and selectivity for NLLGLIEAK were......Peptide imprinted polymers were developed for detection of progastrin releasing peptide (ProGRP); a low abundant blood based biomarker for small cell lung cancer. The polymers targeted the proteotypic nona-peptide sequence NLLGLIEAK and were used for selective enrichment of the proteotypic peptide...... investigated and optimized. Ultimately, a solid phase extraction method was developed for highly selective enrichment of the target peptide from tryptic digests. (C) 2014 Elsevier B.V. All rights reserved....
From antimicrobial to anticancer peptides. A review.
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Diana eGaspar
Full Text Available Antimicrobial peptides (AMPs are part of the innate immune defense mechanism of many organisms. Although AMPs have been essentially studied and developed as potential alternatives for fighting infectious diseases, their use as anticancer peptides (ACPs in cancer therapy either alone or in combination with other conventional drugs has been regarded as a therapeutic strategy to explore. As human cancer remains a cause of high morbidity and mortality worldwide, an urgent need of new, selective and more efficient drugs is evident. Even though ACPs are expected to be selective towards tumor cells without impairing the normal body physiological functions, the development of a selective ACP has been a challenge. It is not yet possible to predict antitumor activity based on ACPs structures. ACPs are unique molecules when compared to the actual chemotherapeutic arsenal available for cancer treatment and display a variety of modes of action which in some types of cancer seem to co-exist. Regardless the debate surrounding the definition of structure-activity relationships for ACPs, great effort has been invested in ACP design and the challenge of improving effective killing of tumor cells remains. As detailed studies on ACPs mechanisms of action are crucial for optimizing drug development, in this review we provide an overview of the literature concerning peptides' structure, modes of action, selectivity and efficacy and also summarize some of the many ACPs studied and/or developed for targeting different solid and hematologic malignancies with special emphasis on the first group. Strategies described for drug development and for increasing peptide selectivity towards specific cells while reducing toxicity are also discussed.
Synergy between a collagen IV mimetic peptide and a somatotropin-domain derived peptide as angiogenesis and lymphangiogenesis inhibitors
Koskimaki, Jacob E.; Lee, Esak; Chen, William; Rivera, Corban G.; Rosca, Elena V.; Pandey, Niranjan B.; Popel, Aleksander S.
Angiogenesis is central to many physiological and pathological processes. Here we show two potent bioinformatically-identified peptides, one derived from collagen IV and translationally optimized, and one from a somatotropin domain-containing protein, synergize in angiogenesis and lymphangiogenesis assays including cell adhesion, migration and in vivo Matrigel plugs. Peptide-peptide combination therapies have recently been applied to diseases such as human immunodeficiency virus (HIV), but re...
Arginine-Rich Peptides Destabilize the Plasma Membrane, Consistent with a Pore Formation Translocation Mechanism of Cell-Penetrating Peptides
Herce, H.D.; Garcia, A. E.; Litt, J.; Kane, R. S.; Martin, P.; Enrique, N.; Rebolledo, A.; Milesi, V.
Recent molecular dynamics simulations (Herce and Garcia, PNAS, 104: 20805 (2007)) have suggested that the arginine-rich HIV Tat peptides might be able to translocate by destabilizing and inducing transient pores in phospholipid bilayers. In this pathway for peptide translocation, arginine residues play a fundamental role not only in the binding of the peptide to the surface of the membrane but also in the destabilization and nucleation of transient pores across the bilayer, despite being char...
Identification of renal natriuretic peptide receptor subpopulations by use of the non-peptide antagonist, HS-142-1.
Rutherford, R A; Matsuda, Y; Wilkins, M R; Polak, J M; Wharton, J
1. The renal actions of natriuretic peptides are dictated by the distribution of guanylyl cyclase-linked (NPRA and NPRB) and non-guanylyl cyclase-linked (NPRC) receptors. Natriuretic peptide receptors have previously been distinguished on the basis of their differential affinity for peptide fragments and analogues; however, most of the available ligands are not fully selective. We have used the specific guanylyl cyclase-linked receptor antagonist, HS-142-1, to investigate the differential dis...
Protein-peptide interactions in mixtures of whey peptides and whey proteins
Creusot, N.; Gruppen, H.
The effects of several conditions on the amounts and compositions of aggregates formed in mixtures of whey protein hydrolysate, made with Bacillus licheniformis protease, and whey protein isolate were investigated using response surface methodology. Next, the peptides present in the aggregates were
A liver metalloendopeptidase which degrades the circulating hypotensive peptide hormones bradykinin and atrial natriuretic peptide
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Carvalho K.M.
Full Text Available A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-200. The purified enzyme hydrolyzed the Pro7-Phe8 bond of bradykinin and the Ser25-Tyr26 bond of atrial natriuretic peptide. No cleavage was produced in other peptide hormones such as vasopressin, oxytocin or Met- and Leu-enkephalin. This enzyme activity was inhibited by 1 mM divalent cation chelators such as EDTA, EGTA and o-phenanthroline and was insensitive to 1 µM phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (EC 184.108.40.206 and angiotensin-converting enzyme (EC 184.108.40.206, respectively. With Mr 85 kDa, the enzyme exhibits optimal activity at pH 7.5. The high affinity of this endopeptidase for bradykinin (Km = 10 µM and for atrial natriuretic peptide (Km = 5 µM suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones.
A study on the C-peptide radioimmunoassay with synthetized connecting peptide
International Nuclear Information System (INIS)
A method of C-peptide radioimmunoassay with the synthetized connecting peptide by Yanaihara was tested for the determination of serum C-peptide immunoreactivity (CPR) in normal people and in diabetics with or without insulin treatment. The CPR value obtained by this method was not interfered with by the presence of serum proteins or by the insulin of people with or without insulin treatment judged by the dilution test and the recovery test. The normal fasting CPR was 2.80 +- 0.78 ng/ml with the synthetized C-peptide as a standard. The CPR value increased and reached a maximum 90 minutes after the ingestion of 50 g of glucose. The increase after the glucose loading reduced corresponding to the severity of diabetes, and some juvenile-onset diabetes showed no response. Adult-type diabetics under insulin treatment, however, showed weak but significant CPR response. The increment of CPR and immunoreactive insulin after glucose loading in normal people and non-treated diabetics was well correlated (γ=0.8262). Judged from the above mentioned results, CPR determination in insulin-treated diabetics was thought to be a useful method for the assessment of the insulin-secreting ability of beta-cells of the pancreas. (J.P.N.)
Antimalarial Activity of Ultra-Short Peptides
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María Yolanda Rios
Full Text Available Ultra-short peptides 1-9 were designed and synthesized with phenylalanine, ornithine and proline amino acid residues and their effect on antimalarial activity was analyzed. On the basis of the IC50 data for these compounds, the effects of nature, polarity, and amino acid sequence on Plasmodium berghei schizont cultures were analyzed too. Tetrapeptides Phe-Orn-Phe-Orn (4 and Lys-Phe-Phe-Orn (5 showed a very important activity with IC50 values of 3.31 and 2.57 μM, respectively. These two tetrapeptides are candidates for subsequent in vivo assays and SARS investigations.
Hepcidin, a new iron regulatory peptide.
Nicolas, Gaël; Viatte, Lydie; Bennoun, Myriam; Beaumont, Carole; Kahn, Axel; Vaulont, Sophie
Maintaining normal iron homeostasis is essential for the organism, as both iron deficiency and iron excess are associated with cellular dysfunction. Recently, several lines of evidence have suggested that hepcidin, a peptide mainly produced by the liver, plays a major role in the control of body iron homeostasis. The subject of this paper is to summarize the advances toward the understanding of function and regulation of hepcidin in iron metabolism and to provide new data on the regulation of hepcidin gene expression by erythropoietin, the major regulator of mammalian erythropoiesis. PMID:12547223
Anticoagulant activity of original synthetic peptide derivatives.
Drozd, N N; Tolstenkov, A S; Makarov, V A; Miphtakhova, N T; Voyushina, T L; Sergeev, M E
Original synthetic peptide derivatives exhibit anticoagulant activity in vitro and in vivo. They delayed fibrin clot formation from human blood plasma in tests for the intrinsic coagulation pathway (activated partial thromboplastin time) and final stage of plasma coagulation (thrombin time) and inhibited amidolytic activity of thrombin. We determined the minimum effective dose of the most active compound providing a 2-fold lengthening of blood clotting time (activated partial thromboplastin time test and thrombin time test), which persisted for 2-3 h. PMID:19024001
DEFF Research Database (Denmark)
Olsen, Christian Adam; Bonke, Gitte; Vedel, Line;
We describe the synthesis and characterization of the first generation of oligomers consisting of alternating repeats of a-amino acids and chiral N-alkyl-ß-alanine (ß-peptoid) residues. These chimeras are stable toward proteolysis, non-hemolytic, and possess antibacterial activity comparable to...... well-known antimicrobial agents. Moreover, the chimeras exhibit length-dependent, concentration-dependent, solvent-dependent, and ion-strength-dependent ellipticity, indicating the presence of a secondary structure in solution. Thus, a-peptide/ß-peptoid oligomers represent a promising novel...
Arginine-rich peptides destabilize the plasma membrane, consistent with a pore formation translocation mechanism of cell-penetrating peptides.
Herce, H D; Garcia, A E; Litt, J; Kane, R S; Martin, P; Enrique, N; Rebolledo, A; Milesi, V
Recent molecular-dynamics simulations have suggested that the arginine-rich HIV Tat peptides translocate by destabilizing and inducing transient pores in phospholipid bilayers. In this pathway for peptide translocation, Arg residues play a fundamental role not only in the binding of the peptide to the surface of the membrane, but also in the destabilization and nucleation of transient pores across the bilayer. Here we present a molecular-dynamics simulation of a peptide composed of nine Args (Arg-9) that shows that this peptide follows the same translocation pathway previously found for the Tat peptide. We test experimentally the hypothesis that transient pores open by measuring ionic currents across phospholipid bilayers and cell membranes through the pores induced by Arg-9 peptides. We find that Arg-9 peptides, in the presence of an electrostatic potential gradient, induce ionic currents across planar phospholipid bilayers, as well as in cultured osteosarcoma cells and human smooth muscle cells. Our results suggest that the mechanism of action of Arg-9 peptides involves the creation of transient pores in lipid bilayers and cell membranes. PMID:19804722
Pulling peptides across nanochannels: resolving peptide binding and translocation through the hetero-oligomeric channel from Nocardia farcinica.
Singh, Pratik Raj; Bárcena-Uribarri, Iván; Modi, Niraj; Kleinekathöfer, Ulrich; Benz, Roland; Winterhalter, Mathias; Mahendran, Kozhinjampara R
We investigated translocation of cationic peptides through nanochannels derived from the Gram-positive bacterium Nocardia farcinica at the single-molecule level. The two subunits NfpA and NfpB form a hetero-oligomeric cation selective channel. On the basis of amino acid comparison we performed homology modeling and obtained a channel structurally related to MspA of Mycobacterium smegmatis. The quantitative single-molecule measurements provide an insight into transport processes of solutes through nanochannels. High-resolution ion conductance measurements in the presence of peptides of different charge and length revealed the kinetics of peptide binding. The observed asymmetry in peptide binding kinetics indicated a unidirectional channel insertion in the lipid bilayer. In the case of cationic peptides, the external voltage acts as a driving force that promotes the interaction of the peptide with the channel surface. At low voltage, the peptide just binds to the channel, whereas at higher voltage, the force is strong enough to pull the peptide across the channel. This allows distinguishing quantitatively between peptide binding and translocation through the channel. PMID:23121560
Construction of HLA/Peptide Tetramer with Peptide-Linked β2 Microglobulin
Institute of Scientific and Technical Information of China (English)
沈传来; ChienchungCHANG; 张建琼; 郭薇; 孟凡岩; 谢维
Analysis of the frequency of antigen-specific cytotoxic T lymphocytes (CTLs) ex vivo is largely dependent on the use of MHC/peptide tetramers. However, the latter reagents have not been widely available, most likely because of their costly and time-consuming production. In this report we utilized an economic strategy to construct HLA/peptide tetramers with recombinant peptide-linked β2 microglobulin (β2m). The HLA-A2-restricted, melanoma antigen MARTl-derived peptide MARTI27-35 (AAGIGILTV) was fused to the N terminus of human β2m through a 15-amino acid (aa)-long linker before being refolded with the recombinant biotinylated HLA-A2 heavy chain ectodomain. The resulted 2-component (2C) monomer was then tetramerized with phycoerythin-labeled streptavidin. The experimental result showed that the 2C HLA-A2/MARTI27-35 monomer was shown to bind to the HLA class Ⅰ complex-specific monoclonal antibody W6/32 and the HLA-A2/MARTI27-35 complex-specific single chain antibody fragment (scFv) 8.3, suggesting the correctness of its specificity. Furthermore, the 2C HLA-A2/MARTI27-35 tetramer detected a specific CD8+ T cell population in HLA-A2-restricted melanoma infiltrating lymphocytes as the conventional 3C HLA-A2/MARTI27-35 tetramer. The yield of 2C HLA-A2/MARTI27-35 monomerwas 2.5 times more than that of the conventional 3C monomer. Taken together, these data indicate that the HLA-A2/MARTI27-35 tetramer can be generated conveniently through the use of MARTI27-35 peptide-β2m fusion proteins, which can facilitate the monitoring of HLA-A2-restricted, MARTl-specific CTL responses in patients with melanoma.
In silico approach for predicting toxicity of peptides and proteins.
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Sudheer Gupta
Full Text Available BACKGROUND: Over the past few decades, scientific research has been focused on developing peptide/protein-based therapies to treat various diseases. With the several advantages over small molecules, including high specificity, high penetration, ease of manufacturing, peptides have emerged as promising therapeutic molecules against many diseases. However, one of the bottlenecks in peptide/protein-based therapy is their toxicity. Therefore, in the present study, we developed in silico models for predicting toxicity of peptides and proteins. DESCRIPTION: We obtained toxic peptides having 35 or fewer residues from various databases for developing prediction models. Non-toxic or random peptides were obtained from SwissProt and TrEMBL. It was observed that certain residues like Cys, His, Asn, and Pro are abundant as well as preferred at various positions in toxic peptides. We developed models based on machine learning technique and quantitative matrix using various properties of peptides for predicting toxicity of peptides. The performance of dipeptide-based model in terms of accuracy was 94.50% with MCC 0.88. In addition, various motifs were extracted from the toxic peptides and this information was combined with dipeptide-based model for developing a hybrid model. In order to evaluate the over-optimization of the best model based on dipeptide composition, we evaluated its performance on independent datasets and achieved accuracy around 90%. Based on above study, a web server, ToxinPred has been developed, which would be helpful in predicting (i toxicity or non-toxicity of peptides, (ii minimum mutations in peptides for increasing or decreasing their toxicity, and (iii toxic regions in proteins. CONCLUSION: ToxinPred is a unique in silico method of its kind, which will be useful in predicting toxicity of peptides/proteins. In addition, it will be useful in designing least toxic peptides and discovering toxic regions in proteins. We hope that the
Evaluating protocols and analytical methods for peptide adsorption experiments.
Fears, Kenan P; Petrovykh, Dmitri Y; Clark, Thomas D
This paper evaluates analytical techniques that are relevant for performing reliable quantitative analysis of peptide adsorption on surfaces. Two salient problems are addressed: determining the solution concentrations of model GG-X-GG, X5, and X10 oligopeptides (G = glycine, X = a natural amino acid), and quantitative analysis of these peptides following adsorption on surfaces. To establish a uniform methodology for measuring peptide concentrations in water across the entire GG-X-GG and X n series, three methods were assessed: UV spectroscopy of peptides having a C-terminal tyrosine, the bicinchoninic acid (BCA) protein assay, and amino acid (AA) analysis. Due to shortcomings or caveats associated with each of the different methods, none were effective at measuring concentrations across the entire range of representative model peptides. In general, reliable measurements were within 30% of the nominal concentration based on the weight of as-received lyophilized peptide. In quantitative analysis of model peptides adsorbed on surfaces, X-ray photoelectron spectroscopy (XPS) data for a series of lysine-based peptides (GGKGG, K5, and K10) on Au substrates, and for controls incubated in buffer in the absence of peptides, suggested a significant presence of aliphatic carbon species. Detailed analysis indicated that this carbonaceous contamination adsorbed from the atmosphere after the peptide deposition. The inferred adventitious nature of the observed aliphatic carbon was supported by control experiments in which substrates were sputter-cleaned by Ar(+) ions under ultra-high vacuum (UHV) then re-exposed to ambient air. In contrast to carbon contamination, no adventitious nitrogen species were detected on the controls; therefore, the relative surface densities of irreversibly-adsorbed peptides were calculated by normalizing the N/Au ratios by the average number of nitrogen atoms per residue. PMID:24706133
Computational Design of Peptide Ligands for Ochratoxin A
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Meike Heurich
Full Text Available In this paper, we describe a peptide library designed by computational modelling and the selection of two peptide sequences showing affinity towards the mycotoxin, ochratoxin A (OTA. A virtual library of 20 natural amino acids was used as building blocks to design a short peptide library against ochratoxin A template using the de novo design program, LeapFrog, and the dynamic modelling software, FlexiDock. Peptide sequences were ranked according to calculated binding scores in their capacity to bind to ochratoxin A. Two high scoring peptides with the sequences N'-Cys-Ser-Ile-Val-Glu-Asp-Gly-Lys-C' (octapeptide and N'-Gly-Pro-Ala-Gly-Ile-Asp-Gly-Pro-Ala-Gly-Ile-Arg-Cys-C' (13-mer were selected for synthesis from the resulting database. These synthesized peptides were characterized using a microtitre plate-based binding assay and a surface plasmon resonance biosensor (Biacore 3000. The binding assay confirmed that both de novo designed peptides did bind to ochratoxin A in vitro. SPR analysis confirmed that the peptides bind to ochratoxin A, with calculated KD values of ~15.7 μM (13-mer and ~11.8 μM (octamer. The affinity of the peptides corresponds well with the molecular modelling results, as the 13-mer peptide affinity is about 1.3-times weaker than the octapeptide; this is in accordance with the binding energy values modelled by FlexiDock. This work illustrates the potential of using computational modelling to design a peptide sequence that exhibits in vitro binding affinity for a small molecular weight toxin.
Pleiotropic action of proinsulin C-peptid
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Michał Usarek
Full Text Available Proinsulin C-peptide, released in equimolar amounts with insulin by pancreatic β cells, since its discovery in 1967 has been thought to be devoid of biological functions apart from correct insulin processing and formation of disulfide bonds between A and B chains. However, in the last two decades research has brought a substantial amount of data indicating a crucial role of C-peptide in regulating various processes in different types of cells and organs. C-peptide acts presumably via either G-protein-coupled receptor or directly inside the cell, after being internalized. However, a receptor binding this peptide has not been identified yet. This peptide ameliorates pathological changes induced by type 1 diabetes mellitus, including glomerular hyperfiltration, vessel endothelium inflammation and neuron demyelinization. In diabetic patients and diabetic animal models, C-peptide substitution in physiological doses improves the functional and structural properties of peripheral neurons and protects against hyperglycemia-induced apoptosis, promoting neuronal development, regeneration and cell survival. Moreover, it affects glycogen synthesis in skeletal muscles. In vitro C-peptide promotes disaggregation of insulin oligomers, thus enhancing its bioavailability and effects on metabolism. There are controversies concerning the biological action of C-peptide, particularly with respect to its effect on Na /K -ATPase activity. Surprisingly, the excess of circulating peptide associated with diabetes type 2 contributes to atherosclerosis development. In view of these observations, long-term, large-scale clinical investigations using C-peptide physiological doses need to be conducted in order to determine safety and health outcomes of long-term administration of C-peptide to diabetic patients.
Nontargeted identification of peptides and disinfection byproducts in water.
Tang, Yanan; Xu, Ying; Li, Feng; Jmaiff, Lindsay; Hrudey, Steve E; Li, Xing-Fang
A broad range of organic compounds are known to exist in drinking water sources and serve as precursors of disinfection byproducts (DBPs). Epidemiological findings of an association of increased risk of bladder cancer with the consumption of chlorinated water has resulted in health concerns about DBPs. Peptides are thought to be an important category of DBP precursors in water. However, little is known about the actual presence of peptides and their DBPs in drinking water because of their high sample complexity and low concentrations. To address this challenge and identify peptides and non-chlorinated/chlorinated peptide DBPs from large sets of organic compounds in water, we developed a novel high throughput analysis strategy, which integrated multiple solid phase extraction (SPE), high performance liquid chromatography (HPLC) separation, and non-target identification using precursor ion exclusion (PIE) high resolution mass spectrometry (MS). After MS analysis, structures of candidate compounds, particularly peptides, were obtained by searching against the Human Metabolome Database (HMDB). Using this strategy, we successfully detected 625 peptides (out of 17,205 putative compounds) and 617 peptides (out of 13,297) respectively in source and finished water samples. The source and finished water samples had 501 peptides and amino acids in common. The remaining 116 peptides and amino acids were unique to the finished water. From a subset of 30 putative compounds for which standards were available, 25 were confirmed using HPLC-MS analysis. By analyzing the peptides identified in source and finished water, we successfully confirmed three disinfection reaction pathways that convert peptides into toxic DBPs. PMID:27090718
Novel antifungal peptides from Ceylon spinach seeds.
Wang, H; Ng, T B
Two novel antifungal peptides, designated alpha- and beta-basrubrins, respectively, were isolated from seeds of the Ceylon spinach Basella rubra. The purification procedure involved saline extraction, (NH(4))(2)SO(4) precipitation, ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-cellulose and FPLC-gel filtration on Superdex peptide column. alpha- and beta-basrubrins exhibited a molecular weight of 4.3 and 5 kDa, respectively. They inhibited translation in a rabbit reticulocyte system with an IC(50) value of 400 and 100 nM, respectively. alpha- and beta-basrubrin inhibited HIV-1 reverse transcriptase by (79.4 +/- 7.8)% and (54.6 +/- 3.6)%, respectively, at a concentration of 400 microM, and (10.56 +/- 0.92)% and (2.12 +/- 0.81)%, respectively, at a concentration of 40 microM. Both alpha- and beta-basrubrins exerted potent antifungal activity toward Botrytis cinerea, Mycosphaerella arachidicola, and Fusarium oxysporum. PMID:11688973
Spider-Venom Peptides as Bioinsecticides
Directory of Open Access Journals (Sweden)
Glenn F. King
Full Text Available Over 10,000 arthropod species are currently considered to be pest organisms. They are estimated to contribute to the destruction of ~14% of the world's annual crop production and transmit many pathogens. Presently, arthropod pests of agricultural and health significance are controlled predominantly through the use of chemical insecticides. Unfortunately, the widespread use of these agrochemicals has resulted in genetic selection pressure that has led to the development of insecticide-resistant arthropods, as well as concerns over human health and the environment. Bioinsecticides represent a new generation of insecticides that utilise organisms or their derivatives (e.g., transgenic plants, recombinant baculoviruses, toxin-fusion proteins and peptidomimetics and show promise as environmentally-friendly alternatives to conventional agrochemicals. Spider-venom peptides are now being investigated as potential sources of bioinsecticides. With an estimated 100,000 species, spiders are one of the most successful arthropod predators. Their venom has proven to be a rich source of hyperstable insecticidal mini-proteins that cause insect paralysis or lethality through the modulation of ion channels, receptors and enzymes. Many newly characterized insecticidal spider toxins target novel sites in insects. Here we review the structure and pharmacology of these toxins and discuss the potential of this vast peptide library for the discovery of novel bioinsecticides.
Resistance to Antimicrobial Peptides in Vibrios
Directory of Open Access Journals (Sweden)
Delphine Destoumieux-Garzón
Full Text Available Vibrios are associated with a broad diversity of hosts that produce antimicrobial peptides (AMPs as part of their defense against microbial infections. In particular, vibrios colonize epithelia, which function as protective barriers and express AMPs as a first line of chemical defense against pathogens. Recent studies have shown they can also colonize phagocytes, key components of the animal immune system. Phagocytes infiltrate infected tissues and use AMPs to kill the phagocytosed microorganisms intracellularly, or deliver their antimicrobial content extracellularly to circumvent tissue infection. We review here the mechanisms by which vibrios have evolved the capacity to evade or resist the potent antimicrobial defenses of the immune cells or tissues they colonize. Among their strategies to resist killing by AMPs, primarily vibrios use membrane remodeling mechanisms. In particular, some highly resistant strains substitute hexaacylated Lipid A with a diglycine residue to reduce their negative surface charge, thereby lowering their electrostatic interactions with cationic AMPs. As a response to envelope stress, which can be induced by membrane-active agents including AMPs, vibrios also release outer membrane vesicles to create a protective membranous shield that traps extracellular AMPs and prevents interaction of the peptides with their own membranes. Finally, once AMPs have breached the bacterial membrane barriers, vibrios use RND efflux pumps, similar to those of other species, to transport AMPs out of their cytoplasmic space.
Short Anabolic Peptides for Bone Growth.
Amso, Zaid; Cornish, Jillian; Brimble, Margaret A
Loss of bone occurs in the age-related skeletal disorder, osteoporosis, leading to bone fragility and increased incidence of fractures, which are associated with enormous costs and substantial morbidity and mortality. Recent data indicate that osteoporotic fractures are more common than other diseases, which usually attract public attention (e.g., heart attack and breast cancer). The prevention and treatment of this skeletal disorder are therefore of paramount importance. Majority of osteoporosis medications restore skeletal balance by reducing osteoclastic activity, thereby reducing bone resorption. These agents, however, do not regenerate damaged bone tissue, leaving limited options for patients once bone loss has occurred. Recently, attention has turned to bone-anabolic agents. Such agents have the ability to increase bone mass and strength, potentially reversing structural damage. To date, only one bone-anabolic drug is available in the market. The discovery of more novel, cost-effective bone anabolic agents is therefore a priority to treat those suffering from this disabling condition. Short peptides offer an important alternative for the development of novel bone-anabolic agents given their high target binding specificity, which translates into potent activity with limited side effects. This review summarizes attempts in the identification of bone-anabolic peptides, and their development for promoting bone growth. PMID:27297498
DAMPD: A manually curated antimicrobial peptide database
Seshadri Sundararajan, Vijayaraghava
The demand for antimicrobial peptides (AMPs) is rising because of the increased occurrence of pathogens that are tolerant or resistant to conventional antibiotics. Since naturally occurring AMPs could serve as templates for the development of new anti-infectious agents to which pathogens are not resistant, a resource that contains relevant information on AMP is of great interest. To that extent, we developed the Dragon Antimicrobial Peptide Database (DAMPD, http://apps.sanbi.ac.za/dampd) that contains 1232 manually curated AMPs. DAMPD is an update and a replacement of the ANTIMIC database. In DAMPD an integrated interface allows in a simple fashion querying based on taxonomy, species, AMP family, citation, keywords and a combination of search terms and fields (Advanced Search). A number of tools such as Blast, ClustalW, HMMER, Hydrocalculator, SignalP, AMP predictor, as well as a number of other resources that provide additional information about the results are also provided and integrated into DAMPD to augment biological analysis of AMPs. The Author(s) 2011. Published by Oxford University Press.
Exhaustive extraction of peptides by electromembrane extraction
DEFF Research Database (Denmark)
Huang, Chuixiu; Gjelstad, Astrid; Pedersen-Bjergaard, Stig
15% (v/v) DEHP was selected as a suitable SLM for exhaustive extraction of peptides under low system-current conditions. Interestingly, increasing the SLM volume from 5 to 10 μL was found to be beneficial for stable and efficient EME. The pH of the sample strongly affected the EME process, and pH 3...... trifluoroacetate, and leu-enkephalin were extracted from 600 μL of 25 mM phosphate buffer (pH 3.5), through a supported liquid membrane (SLM) containing di-(2-ethylhexyl)-phosphate (DEHP) dissolved in an organic solvent, and into 600 μL of an acidified aqueous acceptor solution using a thin flat membrane-based EME...... device. Mass transfer of peptides across the SLM was enhanced by complex formation with the negatively charged DEHP. The composition of the SLM and the extraction voltage were important factors influencing recoveries and current with the EME system. 1-nonanol diluted with 2-decanone (1:1 v/v) containing...
Interaction between antimicrobial peptides and mycobacteria.
Gutsmann, Thomas
Mycobacteria can cause different severe health problems, including tuberculosis (TB). The treatment of TB with conventional antibiotics is successful, however, the number of multi-drug and extensively-drug resistant Mycobacterium tuberculosis strains increases. Moreover, many classical antimycobacterial antibiotics have severe side effects. Therefore, antimicrobial peptides (AMPs) seem to be good candidates for new therapeutic strategies. On the one hand AMPs can be used as a single drug or in combination with conventional antibiotics to directly kill mycobacteria, or on the other hand to act as immunstimulatory agents. This review summarizes the findings on the role of endogenous human AMPs being involved in TB, the antimycobacterial activity of various AMPs, and the molecular modes of action. Most active AMPs interact with the mycobacterial cell envelope and in particular with the mycomembrane and the plasma membrane. The mycomembrane is a very rigid membrane probably leading to a lower activity of the AMPs against mycobacteria as compared to other Gram-negative or Gram-positive bacteria. For some AMPs also other targets have been identified. Because of the complex environment of intracellular mycobacteria being trapped in the phagosome, within the macrophage, within the granuloma, within the lung, the external administration of AMPs in the latent phase of TB is a challenge. However, in the acute phase the AMPs can attack mycobacteria in a direct way. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26851776
Effects of peptide YY on gallbladder motility
International Nuclear Information System (INIS)
The effects of peptide YY (PYY) on cholecystokinin-stimulated gallbladder contraction were investigated in the prairie dog model. Twelve animals underwent laparotomy with catheter placement into the gallbladder and common bile duct (vent). The gallbladder was continuously perfused with [14C]polyethylene glycol-labeled lactated Ringer at 0.03 ml/min, and vent effluent was collected at 2.5-min intervals. All animals received 20 min of intravenous infusion of cholecystokinin octapeptide (CCK-OP), 2.5 ng x kg-1 x min-1, immediately followed by 60-min infusions of either lactated Ringer (LR) or synthetic PYY, 10 or 50 ng x kg-1 x min-1. When LR was infused after CCK-OP, gallbladder filling increased by 15.4 +/- 10.5% with minimal changes in gallbladder pressure. Infusion of PYY10 resulted in a significant increase in gallbladder volume and filling with a significant decrease in intragallbladder pressure. Similar findings were noted with PYY50. These data indicate that synthetic PYY significantly augments gallbladder filling after CCK-OP-stimulated gallbladder contraction. These finding, coupled with the observation that PYY inhibits pancreatic secretion, suggest that this peptide may be the anti-CCK hormone and may have an important role in regulating biliary activity postprandially
Radioiodination of vasoactive intestinal peptide (VIP)
International Nuclear Information System (INIS)
In recent years, increasing biochemical and radiochemical research has been performed to develop radiolabelled peptides as specific ligands for tumour associated receptors. VIP, a 28-amino acid peptide containing two tyrosines and three lysines, has demonstrated that various tumour cells express significantly higher amounts of VIP-receptors and could be applied to the clinic diagnosis. For these purposes, radiohalogenation of VIP by direct and indirect method was studied. Direct labelling works well for radioiodine but is limited to dehalogenation of labelling products in vivo. Conjugate labelling methods including Boltonhunter and wood reagents were developed but introduction of such a molecule to peptides may lead to the decrease of biological activity in vivo. In order to resolve these problems, N-Succinimidyl-3-(tri-nbutylstannyl) benzoate (ATE) was elected for the radioiodination of VIP and already employed to radioiodination of IgG successfully. The in vitro stability and biological activity would be compared in these two methods. Vasoactive intestinal peptide (VIP) and human immunoglobulin (IgG) were radioiodinated by direct and indirect methods. Iodogen was employed in direct method and N-Succinimidyl-3-(tri-n-butylstannyl) benzoate (ATE) was applied as a prosthetic group in the conjugation labelling. The subject of our study was optimizing the radiohalogenation of IgG and VIP followed by separation and analysis of reaction products. The advantages and disadvantages were illustrated by comparing the in vitro stability and biological activity in these two methods. Na123I was prepared by nuclear reaction of 124Te(p, 2n)123I using cyclone-30. More than 95% of radiochemical purity, more than 95% of radionuclide purity and about 100 mCi/mL of radioactivity concentration were obtained. ATE was supplied by Dr. Pozzi and radioiodinated with iodogen and 96% of labelling efficiency was obtained. The stability of radioactive S125IB kept well in dark at 4 . Human Ig
Context Dependent Effects of Chimeric Peptide Morpholino Conjugates Contribute to Dystrophin Exon-skipping Efficiency
Yin, HaiFang; Boisguerin, Prisca; Moulton, Hong M.; Betts, Corinne; Seow, Yiqi; Boutilier, Jordan; Wang, Qingsong; Walsh, Anthony; Lebleu, Bernard; Wood, Matthew JA
We have recently reported that cell-penetrating peptides (CPPs) and novel chimeric peptides containing CPP (referred as B peptide) and muscle-targeting peptide (referred as MSP) motifs significantly improve the systemic exon-skipping activity of morpholino phosphorodiamidate oligomers (PMOs) in dystrophin-deficient mdx mice. In the present study, the general mechanistic significance of the chimeric peptide configuration on the activity and tissue uptake of peptide conjugated PMOs in vivo was ...
Keratin-based peptide : biological evaluation and strengthening properties on relaxed hair
Fernandes, Margarida M.; Lima, Cristóvão F; Loureiro, Ana; Gomes, A. C.; Paulo, Artur Cavaco
A peptide based on a fragment of hair keratin type II cuticular protein, keratin peptide (KP), was studied as a possible strengthening agent for weakened relaxed hair. The peptide was prepared both in aqueous water formulation (WF) and organic solvent formulations (OF), to determine the effect of organic solvents on peptide interaction with hair and the differences in hair recovery. Both peptide formulations were shown to improve mechanical and thermal properties of weakened hair with peptide...
A novel peptide, selected from phage display library of random peptides, can efficiently target into human breast cancer cell
Institute of Scientific and Technical Information of China (English)
DONG Jian; LIU WeiQing; JIANG AiMei; ZHANG KeJian; CHEN MingQing
To develop a targeting vector for breast cancer biotherapy, MDA-MB-231 cell, a human breast cancer cell line, was co-cultured with pC89 (9 aa) phage display library of random peptides. In multiple inde-pendent peptide-presenting phage screening trials, subtilisin was used as a protease to inactivate ex-tra-cellular phages. The internalized phages were collected by cell lysising and amplified in E. coli XLI-Blue. Through five rounds of selection, the peptide-presenting phages which could be internalized in MDA-MB-231 cells were isolated. A comparison was made between internalization capacities of pep-tide-presenting phages isolated from MDA-MB-231 cells and RGD-integrin binding phage by cocultur-ing them with other human tumor cell lines and normal cells. The nucleotide sequences of isolated peptide-presenting phages were then determined by DNA sequencing. To uncover whether phage coat protein or amino acid order was required for the character of the peptide to MDA-MB-231 cells, three peptides were synthesized. They are CASPSGALRSC, ASPSGALRS and CGVIFDHSVPC (the shifted sequence of CASPSGALRSC), and after coculturing them with different cell lines, their targeting ca-pacities to MDA-MB-231 cells were detected. These data suggested that the internalization process was highly selective, and capable of capturing a specific peptide from parent peptide variants. Moreover, the targeting internalization event of peptides was an amino acid sequence dependent manner. The results demonstrated the feasibility of using phage display library of random peptides to develop new targeting system for intracellular delivery of macromolecules, and the peptide we obtained might be modified as a targeting vector for breast cancer gene therapy.
Prediction of Antibacterial Activity from Physicochemical Properties of Antimicrobial Peptides
de Sousa Pereira Simoes de Melo, Manuel; Ferre, Rafael; Feliu, Lidia; Bardaji, Eduard; Planas, Marta; Castanho, Miguel A. R. B.
Consensus is gathering that antimicrobial peptides that exert their antibacterial action at the membrane level must reach a local concentration threshold to become active. Studies of peptide interaction with model membranes do identify such disruptive thresholds but demonstrations of the possible co
Optimization of antibacterial peptides by genetic algorithms and cheminformatics
DEFF Research Database (Denmark)
Fjell, Christopher D.; Jenssen, Håvard; Cheung, Warren A.;
47 of the top rated 50 peptides chosen from an in silico library of nearly 100 000 sequences. Here, we report a method of generating candidate peptide sequences using the heuristic evolutionary programming method of genetic algorithms (GA), which provided a large (19-fold) improvement in...
Neuroprotective peptides as drug candidates against Alzheimer's diasease
Czech Academy of Sciences Publication Activity Database
Patočka, J.; Slaninová, Jiřina; Kunešová, G.
Roč. 3, - (2005), 67-73. ISSN 1214-021X R&D Projects: GA ČR(CZ) GA305/03/1100 Institutional research plan: CEZ:AV0Z40550506 Keywords : Alzheimers's disease * neuroprotective peptide * Abeta peptide Subject RIV: CE - Biochemistry
A highly scalable peptide-based assay system for proteomics.
Directory of Open Access Journals (Sweden)
Igor A Kozlov
Full Text Available We report a scalable and cost-effective technology for generating and screening high-complexity customizable peptide sets. The peptides are made as peptide-cDNA fusions by in vitro transcription/translation from pools of DNA templates generated by microarray-based synthesis. This approach enables large custom sets of peptides to be designed in silico, manufactured cost-effectively in parallel, and assayed efficiently in a multiplexed fashion. The utility of our peptide-cDNA fusion pools was demonstrated in two activity-based assays designed to discover protease and kinase substrates. In the protease assay, cleaved peptide substrates were separated from uncleaved and identified by digital sequencing of their cognate cDNAs. We screened the 3,011 amino acid HCV proteome for susceptibility to cleavage by the HCV NS3/4A protease and identified all 3 known trans cleavage sites with high specificity. In the kinase assay, peptide substrates phosphorylated by tyrosine kinases were captured and identified by sequencing of their cDNAs. We screened a pool of 3,243 peptides against Abl kinase and showed that phosphorylation events detected were specific and consistent with the known substrate preferences of Abl kinase. Our approach is scalable and adaptable to other protein-based assays.
Novel antimicrobial peptides from the venom of solitary bees
Czech Academy of Sciences Publication Activity Database
Čeřovský, Václav; Cvačka, Josef; Voburka, Zdeněk; Hovorka, Oldřich; Slaninová, Jiřina; Fučík, Vladimír; Bednárová, Lucie
Roč. 14, č. 8 (2008), s. 92-92. ISSN 1075-2617. [European Peptide Symposium /30./. 31.08.2008-05.09.2008, Helsinki] Institutional research plan: CEZ:AV0Z40550506 Keywords : antimicrobial peptides * solitary bees * melectin * isolation and characterization Subject RIV: CC - Organic Chemistry
Peptide Nucleic Acids Having Amino Acid Side Chains
DEFF Research Database (Denmark)
A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than the corresponding DNA or RNA strands, and exhibit increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a group consisting of...
Constraining cyclic peptides to mimic protein structure motifs
DEFF Research Database (Denmark)
Hill, Timothy A.; Shepherd, Nicholas E.; Diness, Frederik;
Many proteins exert their biological activities through small exposed surface regions called epitopes that are folded peptides of well-defined three-dimensional structures. Short synthetic peptide sequences corresponding to these bioactive protein surfaces do not form thermodynamically stable pro...
Peptide separation of commercial fermented milk during refrigerated storage
Directory of Open Access Journals (Sweden)
Luis Guillermo González-Olivares
Full Text Available Milk is an important source of bioactive compounds. Many of these compounds are released during fermentation and refrigerated storage. The aim of this study was to determine the release of peptides by lactic acid bacteria in commercial fermented milk during refrigerated storage. The size and profile of peptides were analyzed by polyacrylamide gel electrophoresis and sizeexclusion HPLC. During electrophoresis, it was observed that the peptides were released from caseins, whereas β-lactoglobulin was the whey protein with the highest degradation. HPLC analysis confirmed the pattern of peptide formation observed in electrophoresis. Two fractions lower than 2 kDa with aromatic amino acids in their structure were separated. These results were consistent with those reported for structures of peptides with antihypertensive activity. Therefore, the presence of aromatic amino acids in the peptide fractions obtained increases the likelihood of finding peptides with such activity in refrigerated commercial fermented milk. In conclusion, during cold storage, peptides with different molecular weights are released and accumulated. This could be due to the action of proteinases and peptidases of the proteolytic system in lactic acid bacteria.
Cycloaddition in peptides for high-capacity optical storage
DEFF Research Database (Denmark)
Lohse, Brian; Berg, Rolf Henrik; Hvilsted, Søren;
Photodimerization of chromophores attached to a short peptide chain is investigated for high-capacity optical digital storage with UV lasers. The length and rigidity of the peptide chain assure an optimal distance and orientation of the chromophores for effective photodimerization. Using a theory...
History and diagnostic significance of C-peptide.
Brandenburg, Dietrich
Starting with the epoch-making discovery of proinsulin, C-peptide has played an important interdisciplinary role, both as part of the single-chain precursor molecule and as an individual entity. In the pioneering years, fundamental systematic experiments unravelled new biochemical mechanisms and chemical structures. After the first detection of C-peptide in human serum, it quickly became a most useful independent indicator of insulin biosynthesis and secretion, finding application in a rapidly growing number of clinical investigations. A prerequisite was the development of specific immuno assays for proinsulin and C-peptide. Further milestones were: the chemical synthesis of several C-peptides and the accomplishments in the synthesis of proinsulin; the detection of preproinsulin with its bearings on understanding protein biosynthesis; the pioneering role of insulin, proinsulin, C-peptide, and mini-C-peptides in the development of recombinant DNA technology; and the discovery of the enzymes for the endoproteolytic processing of proinsulin into insulin and C-peptide, completing the pathway of biosynthesis. Today, C-peptide continues to serve as a special diagnostic tool in Diabetology and related fields. Thus, its passive role is well established. Evidence for its active role in physiology and pathophysiology is more recent and is subject of the following contributions. PMID:18509495
Information-driven modeling of protein-peptide complexes.
Trellet, Mikael; Melquiond, Adrien S J; Bonvin, Alexandre M J J
Despite their biological importance in many regulatory processes, protein-peptide recognition mechanisms are difficult to study experimentally at the structural level because of the inherent flexibility of peptides and the often transient interactions on which they rely. Complementary methods like biomolecular docking are therefore required. The prediction of the three-dimensional structure of protein-peptide complexes raises unique challenges for computational algorithms, as exemplified by the recent introduction of protein-peptide targets in the blind international experiment CAPRI (Critical Assessment of PRedicted Interactions). Conventional protein-protein docking approaches are often struggling with the high flexibility of peptides whose short sizes impede protocols and scoring functions developed for larger interfaces. On the other side, protein-small ligand docking methods are unable to cope with the larger number of degrees of freedom in peptides compared to small molecules and the typically reduced available information to define the binding site. In this chapter, we describe a protocol to model protein-peptide complexes using the HADDOCK web server, working through a test case to illustrate every steps. The flexibility challenge that peptides represent is dealt with by combining elements of conformational selection and induced fit molecular recognition theories. PMID:25555727
Chemo-enzymatic peptide synthesis : bioprocess engineering aspects
Vossenberg, P.
Peptides, in particular oligopeptides, play an important role in the fields of health care, nutrition and cosmetics. Chemical synthesis is currently the most mature technique for the synthesis of peptides that range in length from 5 to 80 amino acids. Chemical synthesis is, however, expected
C-Peptide Effects on Renal Physiology and Diabetes
Directory of Open Access Journals (Sweden)
L. Rebsomen
Full Text Available The C-peptide of proinsulin is important for the biosynthesis of insulin and has for a long time been considered to be biologically inert. Animal studies have shown that some of the renal effects of the C-peptide may in part be explained by its ability to stimulate the Na,K-ATPase activity. Precisely, the C-peptide reduces diabetes-induced glomerular hyperfiltration both in animals and humans, therefore, resulting in regression of fibrosis. The tubular function is also concerned as diabetic animals supplemented with C-peptide exhibit better renal function resulting in reduced urinary sodium waste and protein excretion together with the reduction of the diabetes-induced glomerular hyperfiltration. The tubular effectors of C-peptide were considered to be tubule transporters, but recent studies have shown that biochemical pathways involving cellular kinases and inflammatory pathways may also be important. The matter theory concerning the C-peptide effects is a metabolic one involving the effects of the C-peptide on lipidic metabolic status.This review concentrates on the most convincing data which indicate that the C-peptide is a biologically active hormone for renal physiology.
Studies on human proinsulin.C-peptide radioimmunoassay method
International Nuclear Information System (INIS)
125I-labelled human.C-peptide was prepared by the chloramin T method, the enzymic method and the active ester method, respectively. Using respective 125I-labelled human.C-peptides in human proinsulin.C-peptide RIA, we compared the binding (B0/T %) to antibody, displacement by standard human.C-peptide, recovery, and stability. The usable 125I-labelled antigen for human proinsulin.C-peptide RIA could be prepared by the chloramin T method and the enzymic method which labelled 125I to tyrosyl human proinsulin connecting peptide, and by an active ester method which conjugates 125I-labelled active ester to human proinsulin connecting peptide. No differences among those 125I-labelled antigens were observed in displacement (B/B0 %) by standard human.C-peptide or the recovery test. In the case of constant preparation of 125I-labelled antigen for RIA, the enzymic method was the best from the viewpoint that reaction ratio is stable and the stability of B0/T % was good. (auth.)
Structure-activity relationship of CART peptide fragments
Czech Academy of Sciences Publication Activity Database
Maletínská, Lenka; Maixnerová, Jana; Hlaváček, Jan; Blokešová, Darja; Elbert, Tomáš; Šanda, Miloslav; Slaninová, Jiřina; Železná, Blanka
Roč. 88, č. 4 (2007), s. 565. ISSN 0006-3525. [American Peptide Society Symposium /20./. 26.06.2007-30.06.2007, Montreal] Institutional research plan: CEZ:AV0Z40550506 Keywords : cocaine and amphetamine regulated transcript peptide * structure * activity Subject RIV: CE - Biochemistry
The Bacterial Surface Layer Provides Protection against Antimicrobial Peptides
de la Fuente-Núñez, César; Mertens, Jan; Smit, John; Hancock, Robert E. W.
This report describes a previously unrecognized role for bacterial surface layers as barriers that confer protection against antimicrobial peptides. As antimicrobial peptides exist in natural environments, S-layers may provide a bacterial survival mechanism that has been selected for through evolution.
Method for synthesizing peptides with saccharide linked enzyme polymer conjugates
Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.
A method is disclosed for synthesizing peptides using water soluble enzyme polymer conjugates. The method comprises catalyzing the peptide synthesis with enzyme which has been covalently bonded to a polymer through at least three linkers which linkers have three or more hydroxyl groups. The enzyme is conjugated at lysines or arginines. 19 figs.
Neuromedin and FN-38 Peptides for Treating Psychiatric Diseases
Methods and compositions for treating psychiatric diseases and disorders are disclosed. The methods provided generally involve the administration of an NMX peptide, an FNX peptide, or an NMX receptor agonist, or analogs or derivatives thereof, to a subject in order to treat psychiatric diseases and ...
Cell-penetrating peptides for drug delivery across membrane barriers
DEFF Research Database (Denmark)
Foged, Camilla; Nielsen, Hanne Moerck
-penetrating peptides as transmembrane drug delivery agents, according to the recent literature, and discusses critical issues and future challenges in relation to fully understanding the fundamental principles of the cell-penetrating peptide-mediated membrane translocation of cargoes and the exploitation of their...
Design, synthesis and analysis of novel Smac-based peptides
Czech Academy of Sciences Publication Activity Database
Georgieva, M.; Dzimbova, T.; Sázelová, Petra; Detcheva, R.; Kašička, Václav; Pajpanova, T.
Roč. 20, Suppl S1 (2014), S225-S226. ISSN 1075-2617. [European Peptide Symposium /33./. 31.08.2014-05.09.2014, Sofia] Institutional support: RVO:61388963 Keywords : apoptotic peptides * Smac-mimetics * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation
Peptide_YY - Wikipedia, the free encyclopedia [Gene Wiki
Lifescience Database Archive (English)
Full Text Available Peptide YY - Wikipedia, the free encyclopediaPeptide YYFrom Wikipedia, the free encyclopediaJump ... d by 30% in obese subjects (P<0.001) and 31% in lean ... subjects (P<0.001).[13]While some studies have ...
Peptide-membrane Interactions by Spin-labeling EPR
Smirnova, Tatyana I.; Smirnov, Alex I.
Site-directed spin labeling (SDSL) in combination with Electron Paramagnetic Resonance (EPR) spectroscopy is a well-established method that has recently grown in popularity as an experimental technique, with multiple applications in protein and peptide science. The growth is driven by development of labeling strategies, as well as by considerable technical advances in the field, that are paralleled by an increased availability of EPR instrumentation. While the method requires an introduction of a paramagnetic probe at a well-defined position in a peptide sequence, it has been shown to be minimally destructive to the peptide structure and energetics of the peptide-membrane interactions. In this chapter, we describe basic approaches for using SDSL EPR spectroscopy to study interactions between small peptides and biological membranes or membrane mimetic systems. We focus on experimental approaches to quantify peptide-membrane binding, topology of bound peptides, and characterize peptide aggregation. Sample preparation protocols including spin-labeling methods and preparation of membrane mimetic systems are also described. PMID:26477253
Radiation-induced products of peptides and their enzymatic digestibility
International Nuclear Information System (INIS)
Chemical characterization of radiation-induced products of peptides and proteins is essential for understanding the effect of ionizing radiation on peptides and proteins. Furthermore, peptides containing radiation-altered amino acid residues might not be completely digestible by proteolytic enzymes. In this work, small homopeptides of Ala, Phe and Met were chosen as model peptides. Lysozyme was used to investigate the effect of ionizing radiation on a small protein. All peptides and lysozyme were irradiated in diluted, oxygen free, N2O-saturated aqueous solutions, using a 60Co-γ-source. HPLC, capillary GC and GC-MS were applied to isolate and characterize the radiation-induced products. The enzymatic digestibility of the products was investigated using aminopeptidase M, leucine aminopeptidase, carboxypeptidase A and carboxypeptidase Y. It was found that irradiation of peptides examined in this work leads to racemization and alteration of amino acid residues and crosslinks between the peptide chains. In addition, it was established that exopeptidases act differently on radiation-induced dimers of peptides composed of aliphatic, aromatic and sulfur-containing amino acids
Chemical instability of pharmaceutical peptides in polymeric controlled release systems
Shirangi, M.
Peptide and protein drugs are presently an important class of pharmaceuticals due to their favorable properties, i.e. high and selective activity. However, peptides and proteins are relatively sensitive for degradation and therefore there is need for investigation of the chemical stability of these
Optimization for Peptide Sample Preparation for Urine Peptidomics
Energy Technology Data Exchange (ETDEWEB)
Sigdel, Tara K.; Nicora, Carrie D.; Hsieh, Szu-Chuan; Dai, Hong; Qian, Weijun; Camp, David G.; Sarwal, Minnie M.
Analysis of native or endogenous peptides in biofluids can provide valuable insights into disease mechanisms. Furthermore, the detected peptides may also have utility as potential biomarkers for non-invasive monitoring of human diseases. The non-invasive nature of urine collection and the abundance of peptides in the urine makes analysis by high-throughput 'peptidomics' methods , an attractive approach for investigating the pathogenesis of renal disease. However, urine peptidomics methodologies can be problematic with regards to difficulties associated with sample preparation. The urine matrix can provide significant background interference in making the analytical measurements that it hampers both the identification of peptides and the depth of the peptidomics read when utilizing LC-MS based peptidome analysis. We report on a novel adaptation of the standard solid phase extraction (SPE) method to a modified SPE (mSPE) approach for improved peptide yield and analysis sensitivity with LC-MS based peptidomics in terms of time, cost, clogging of the LC-MS column, peptide yield, peptide quality, and number of peptides identified by each method. Expense and time requirements were comparable for both SPE and mSPE, but more interfering contaminants from the urine matrix were evident in the SPE preparations (e.g., clogging of the LC-MS columns, yellowish background coloration of prepared samples due to retained urobilin, lower peptide yields) when compared to the mSPE method. When we compared data from technical replicates of 4 runs, the mSPE method provided significantly improved efficiencies for the preparation of samples from urine (e.g., mSPE peptide identification 82% versus 18% with SPE; p = 8.92E-05). Additionally, peptide identifications, when applying the mSPE method, highlighted the biology of differential activation of urine peptidases during acute renal transplant rejection with distinct laddering of specific peptides, which was obscured for most proteins
A novel affinity purification method to isolate peptide specific antibodies
DEFF Research Database (Denmark)
Karlsen, Alan E; Lernmark, A; Kofod, Hans; Dyrberg, T
affinity-purify anti-peptide antibodies. To test our system, rabbits were immunized with model peptides representing sequences of the putative rabbit growth hormone receptor and several HLA-DQ beta-chain molecules. Polystyrene plastic beads were coated with peptides. Immune serum was incubated with the...... beads and after a wash step the bound antibodies were eluted in 1 M acetic acid. The eluted material was composed predominantly of intact immunoglobulin as evidenced by the presence of heavy and light chain bands in SDS-PAGE. The eluted antibodies were peptide specific in ELISA and bound only to intact......, antigenic protein in immunoblot analyses. The sequence-specific nature of the eluted antibodies was confirmed since binding to the antigenic proteins could be displaced by the immunizing but not by unrelated peptides....
Bioprinting synthetic self-assembling peptide hydrogels for biomedical applications.
Loo, Yihua; Hauser, Charlotte A E
Three-dimensional (3D) bioprinting is a disruptive technology for creating organotypic constructs for high-throughput screening and regenerative medicine. One major challenge is the lack of suitable bioinks. Short synthetic self-assembling peptides are ideal candidates. Several classes of peptides self-assemble into nanofibrous hydrogels resembling the native extracellular matrix. This is a conducive microenvironment for maintaining cell survival and physiological function. Many peptides also demonstrate stimuli-responsive gelation and tuneable mechanical properties, which facilitates extrusion before dispensing and maintains the shape fidelity of the printed construct in aqueous media. The inherent biocompatibility and biodegradability bodes well for in vivo applications as implantable tissues and drug delivery matrices, while their short length and ease of functionalization facilitates synthesis and customization. By applying self-assembling peptide inks to bioprinting, the dynamic complexity of biological tissue can be recreated, thereby advancing current biomedical applications of peptide hydrogel scaffolds. PMID:26694103
Antimicrobial activity of mosquito cecropin peptides against Francisella.
Kaushal, Akanksha; Gupta, Kajal; Shah, Ruhee; van Hoek, Monique L
Francisella tularensis is the cause of the zoonotic disease tularemia. In Sweden and Scandinavia, epidemiological studies have implicated mosquitoes as a vector. Prior research has demonstrated the presence of Francisella DNA in infected mosquitoes but has not shown definitive transmission of tularemia from a mosquito to a mammalian host. We hypothesized that antimicrobial peptides, an important component of the innate immune system of higher organisms, may play a role in mosquito host-defense to Francisella. We established that Francisella sp. are susceptible to two cecropin antimicrobial peptides derived from the mosquito Aedes albopictus as well as Culex pipiens. We also demonstrated induced expression of Aedes albopictus antimicrobial peptide genes by Francisella infection C6/36 mosquito cell line. We demonstrate that mosquito antimicrobial peptides act against Francisella by disrupting the cellular membrane of the bacteria. Thus, it is possible that antimicrobial peptides may play a role in the inability of mosquitoes to establish an effective natural transmission of tularemia. PMID:27235883
Epithelial antimicrobial peptides in host defense against infection
Directory of Open Access Journals (Sweden)
Bals Robert
Full Text Available Abstract One component of host defense at mucosal surfaces seems to be epithelium-derived antimicrobial peptides. Antimicrobial peptides are classified on the basis of their structure and amino acid motifs. Peptides of the defensin, cathelicidin, and histatin classes are found in humans. In the airways, α-defensins and the cathelicidin LL-37/hCAP-18 originate from neutrophils. β-Defensins and LL-37/hCAP-18 are produced by the respiratory epithelium and the alveolar macrophage and secreted into the airway surface fluid. Beside their direct antimicrobial function, antimicrobial peptides have multiple roles as mediators of inflammation with effects on epithelial and inflammatory cells, influencing such diverse processes as proliferation, immune induction, wound healing, cytokine release, chemotaxis, protease-antiprotease balance, and redox homeostasis. Further, antimicrobial peptides qualify as prototypes of innovative drugs that might be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation.
β-Peptide bundles: Design. Build. Analyze. Biosynthesize.
Wang, Pam S P; Schepartz, Alanna
Peptides containing β-amino acids are unique non-natural polymers known to assemble into protein-like tertiary and quaternary structures. When composed solely of β-amino acids, the structures formed, defined assemblies of 14-helices called β-peptide bundles, fold cooperatively in water solvent into unique and discrete quaternary assemblies that are highly thermostable, bind complex substrates and metal ion cofactors, and, in certain cases, catalyze chemical reactions. In this Perspective, we recount the design and elaboration of β-peptide bundles and provide an outlook on recent, unexpected discoveries that could influence research on β-peptides and β-peptide bundles (and β-amino acid-containing proteins) for decades to come. PMID:27146019
Cationic Cell-Penetrating Peptides Are Potent Furin Inhibitors.
Directory of Open Access Journals (Sweden)
Bruno Ramos-Molina
Full Text Available Cationic cell-penetrating peptides have been widely used to enhance the intracellular delivery of various types of cargoes, such as drugs and proteins. These reagents are chemically similar to the multi-basic peptides that are known to be potent proprotein convertase inhibitors. Here, we report that both HIV-1 TAT47-57 peptide and the Chariot reagent are micromolar inhibitors of furin activity in vitro. In agreement, HIV-1 TAT47-57 reduced HT1080 cell migration, thought to be mediated by proprotein convertases, by 25%. In addition, cyclic polyarginine peptides containing hydrophobic moieties which have been previously used as transfection reagents also exhibited potent furin inhibition in vitro and also inhibited intracellular convertases. Our finding that cationic cell-penetrating peptides exert potent effects on cellular convertase activity should be taken into account when biological effects are assessed.
Effects of Peptide Adsorption on the Electronic Properties of Graphene
Akdim, Brahim; Kuang, Zhifeng; Kim, Sang; Naik, Rajesh; Farmer, Barry; Walsh, Tiffany; Pachter, Ruth
In this work we aim to explain the increase in the electrical conductance in a single-layer graphene (SLG) field-effect transistor (FET) upon binding the peptide HSSYWYAFNNKT, which we previously demonstrated. The adsorption of the peptide onto the SLG has been carefully modeled by applying empirical molecular dynamics simulations with the AMOEBA force-field. The peptide adsorbed SLG structure demonstrates π-π stacking with aromatic amino acids, namely His,Tyr, Thr and Ph. Based on this large-scale peptide-SLG system, calculations on the electron transport using the nonequilibrium Green's function formalism at the extended Huckel level were carried out. Transmission eigenchannels and spectra, projected density of states, effects of modeling realistic leads (gold vs. graphene) and I-V characteristics will be discussed in detail. In this context, suppositions as to the mechanism of increased conductance for the peptide-SLG FET will be proposed.
Interaction of peptides with cell membranes: insights from molecular modeling
International Nuclear Information System (INIS)
The investigation of the interaction of peptides with cell membranes is the focus of active research. It can enhance the understanding of basic membrane functions such as membrane transport, fusion, and signaling processes, and it may shed light on potential applications of peptides in biomedicine. In this review, we will present current advances in computational studies on the interaction of different types of peptides with the cell membrane. Depending on the properties of the peptide, membrane, and external environment, the peptide–membrane interaction shows a variety of different forms. Here, on the basis of recent computational progress, we will discuss how different peptides could initiate membrane pores, translocate across the membrane, induce membrane endocytosis, produce membrane curvature, form fibrils on the membrane surface, as well as interact with functional membrane proteins. Finally, we will present a conclusion summarizing recent progress and providing some specific insights into future developments in this field. (topical review)
Cathelicidin peptides as candidates for a novel class of antimicrobials.
Zanetti, Margherita; Gennaro, Renato; Skerlavaj, Barbara; Tomasinsig, Linda; Circo, Raffaella
Cathelicidin peptides are a numerous group of mammalian cationic antimicrobial peptides. Despite a common evolutionary origin of their genes, peptides display a remarkable variety of sizes, sequences and structures. Their spectra of antimicrobial activity are varied and cover a range of organisms that includes bacteria, fungi and enveloped viruses. In addition, they bind to and neutralize the effects of endotoxin. These features make this family of peptides good candidates in view of a therapeutic use. The most promising ones are currently under evaluation as leads for the development of novel anti-infectives, and synthetic variants are in an advanced stage of development for specific clinical applications. This review focuses on recent studies on the structure and in vitro and in vivo biological activities of these peptides. PMID:11945171
Describing the Peptide Binding Specificity of HLA-C
DEFF Research Database (Denmark)
Rasmussen, Michael; Harndahl, Mikkel Nors; Nielsen, Morten;
for 5 HLA-C molecules and for all, but one, molecule we find a high frequency of binders, >70%, among these peptides. To extend the examined peptide space, we use bioinformatic prediction tools to search for additional binders. Finally, we update our prediction tool, NetMHCpan, with the HLA-C affinity......Human leukocyte antigen (HLA) presents peptides to T-cells for immune scrutiny. Whereas HLA-A and -B have been described in great detail, HLA-C has received much less attention. Here, to increase the coverage of HLA-C and the accuracy of the corresponding tools, we have generated HLA-C molecules......; peptide-binding assays, data and predictors; and tetramers; representing the most prevalent HLA-C molecules. We have combined positional scanning combinatorial peptide library (PSCPL) with a homogenous high-throughput dissociation assay and generated specificity matrices for 11 different HLA-C molecules...
Peptide folding in the presence of interacting protein crowders
Bille, Anna; Mohanty, Sandipan; Irbäck, Anders
Using Monte Carlo methods, we explore and compare the effects of two protein crowders, BPTI and GB1, on the folding thermodynamics of two peptides, the compact helical trp-cage and the β-hairpin-forming GB1m3. The thermally highly stable crowder proteins are modeled using a fixed backbone and rotatable side-chains, whereas the peptides are free to fold and unfold. In the simulations, the crowder proteins tend to distort the trp-cage fold, while having a stabilizing effect on GB1m3. The extent of the effects on a given peptide depends on the crowder type. Due to a sticky patch on its surface, BPTI causes larger changes than GB1 in the melting properties of the peptides. The observed effects on the peptides stem largely from attractive and specific interactions with the crowder surfaces, and differ from those seen in reference simulations with purely steric crowder particles.
Photodissociation pathways and lifetimes of protonated peptides and their dimers
DEFF Research Database (Denmark)
Gopalan, Aravind; Klærke, Benedikte; Rajput, Jyoti;
Photodissociation lifetimes and fragment channels of gas-phase, protonated YAn (n = 1,2) peptides and their dimers were measured with 266 nm photons. The protonated monomers were found to have a fast dissociation channel with an exponential lifetime of ∼200 ns while the protonated dimers show an...... channel in the dimer was found to result in cleavage of the H-bonds after energy transfer through these H-bonds. In general, the dissociation of these protonated peptides is non-prompt and the decay time was found to increase with the size of the peptides. Quantum RRKM calculations of the microcanonical...... equipartition theorem. It demonstrates encouraging results in predicting fragmentation lifetimes of protonated peptides. Finally, we present the first experimental evidence for a photo-induced conversion of tyrosine-containing peptides into monocyclic aromatic hydrocarbon along with a formamide molecule both...
Peptide synthesis on glass substrate using acoustic droplet ejector.
Youngki Choe; Shih-Jui Chen; Eun Sok Kim
This paper describes the synthesis of a 9-mers-long peptide ladder structure of glycine on a modified glass surface using a nanoliter droplet ejector. To synthesize peptide on a glass substrate, SPOT peptide synthesis protocol was followed with a nozzleless acoustic droplet ejector being used to eject about 300 droplets of preactivated amino acid solution to dispense 60 nL of the solution per mer. The coupling efficiency of each mer was measured with FITC fluorescent tag to be 96%, resulting in net 70% efficiency for the whole 9-mer-long peptide of glycine. Usage of a nanoliter droplet ejector for SPOT peptide synthesis increases the density of protein array on a chip. PMID:24235271
Atomic scale insights into urea-peptide interactions in solution.
Steinke, Nicola; Gillams, Richard J; Pardo, Luis Carlos; Lorenz, Christian D; McLain, Sylvia E
The mechanism by which proteins are denatured by urea is still not well understood, especially on the atomic scale where these interactions occur in vivo. In this study, the structure of the peptide GPG has been investigated in aqueous urea solutions in order to understand the combination of roles that both urea and water play in protein unfolding. Using a combination of neutron diffraction enhanced by isotopic substitution and computer simulations, it was found, in opposition with previous simulations studies, that urea is preferred over water around polar and charged portions of the peptides. Further, it appears that while urea directly replaces water around the nitrogen groups on GPG that urea and water occupy different positions around the peptide bond carbonyl groups. This suggests that urea may in fact weaken the peptide bond, disrupting the peptide backbone, thus ultimately causing denaturation. PMID:26764567
Interactions of Gastrointestinal Peptides: Ghrelin and Its Anorexigenic Antagonists
Directory of Open Access Journals (Sweden)
Anna-Sophia Wisser
Full Text Available Food intake behaviour and energy homeostasis are strongly regulated by a complex system of humoral factors and nerval structures constituting the brain-gut-axis. To date the only known peripherally produced and centrally acting peptide that stimulates food intake is ghrelin, which is mainly synthesized in the stomach. Recent data indicate that the orexigenic effect of ghrelin might be influenced by other gastrointestinal peptides such as cholecystokinin (CCK, bombesin, desacyl ghrelin, peptide YY (PYY, as well as glucagon-like peptide (GLP. Therefore, we will review on the interactions of ghrelin with several gastrointestinal factors known to be involved in appetite regulation in order to elucidate the interdependency of peripheral orexigenic and anorexigenic peptides in the control of appetite.
Characterization of foot-and-mouth disease virus's viral peptides with LC-ESI-MS
International Nuclear Information System (INIS)
Peptides and proteins play a central role in numerous biological and physiological processes in living organisms. Viral capsid peptides are part of the viruses' outer shell of genetic materials. Viruses are recognized by immune system via capsid peptides. Depending on this property of capsid peptides, prototypes synthetic peptide-based vaccine can be developed. In this work, we synthesized three different viral peptide sequences of foot-and-mouth disease virus with microwave enhanced solid phase synthesis method. These peptides were characterized by using liquid chromatography electro spray interface mass spectrometry (LC-ESI-MS) with electro spray ionization. We briefly describe the essential facts for peptide characterization. (author)
Directory of Open Access Journals (Sweden)
L. Depau
Full Text Available Detection of new tumor-selective targets, which allow either cancer cell tracing or therapy, is a crucial issue in cancer research. Membrane receptors for endogenous peptides such as Neurotensin are over-expressed in many human cancers and could therefore be used as tumor-specific antigen, while peptide ligands might act as targeting agents. The development of peptides as drug has always been limited by their short half-life, due to degradation by peptidases and proteases. Chemical modification, which can stabilize the molecules, may modify peptide affinity or specificity. More- over, coupling of peptides to effector units for imaging or therapy, may interfere with biological activity. We demonstrated that peptide sequences, when synthesized in an oligo-branched form, be- come resistant to proteolysis and thank to their multimericity are more efficient than correspon- ding monomers in binding cellular antigens1. Moreover, the branched core allow coupling of effector units without affecting peptide activity. Drug-armed tetra-branched neurotensin peptides (NT4 were synthesized with different conjugation methods, resulting either in uncleavable adducts or drug-releasing molecules2-4. Recently we de- veloped DOPC liposomes filled with the cytotoxic drug Doxorubicin (Doxo and functionalized with NT4. Armed DOPC liposomes showed a clear advantage with respect to nude liposomes in drug internalization and their cytotoxicity is fourfold increased with respect to the same nude lipo- somes. Conjugation to NT4 switches drug internalization to a peptide-receptor mediated mechanism, which greatly increases drug selectivity and also might allow by-passing drug cell resistance. In vitro and in vivo results indicated that branched NT peptides are valuable tools for tumor selective targeting.
Biodegradable copolymers carrying cell-adhesion peptide sequences.
Proks, Vladimír; Machová, Lud'ka; Popelka, Stepán; Rypácek, Frantisek
Amphiphilic block copolymers are used to create bioactive surfaces on biodegradable polymer scaffolds for tissue engineering. Cell-selective biomaterials can be prepared using copolymers containing peptide sequences derived from extracellular-matrix proteins (ECM). Here we discuss alternative ways for preparation of amphiphilic block copolymers composed of hydrophobic polylactide (PLA) and hydrophilic poly(ethylene oxide) (PEO) blocks with cell-adhesion peptide sequences. Copolymers PLA-b-PEO were prepared by a living polymerisation of lactide in dioxane with tin(II)2-ethylhexanoate as a catalyst. The following approaches for incorporation of peptides into copolymers were elaborated. (a) First, a side-chain protected Gly-Arg-Gly-Asp-Ser-Gly (GRGDSG) peptide was prepared by solid-phase peptide synthesis (SPPS) and then coupled with delta-hydroxy-Z-amino-PEO in solution. In the second step, the PLA block was grafted to it via a controlled polymerisation of lactide initiated by the hydroxy end-groups of PEO in the side-chain-protected GRGDSG-PEO. Deprotection of the peptide yielded a GRGDSG-b-PEO-b-PLA copolymer, with the peptide attached through its C-end. (b) A protected GRGDSG peptide was built up on a polymer resin and coupled with Z-carboxy-PEO using a solid-phase approach. After cleavage of the delta-hydroxy-PEO-GRGDSG copolymer from the resin, polymerisation of lactide followed by deprotection of the peptide yielded a PLA-b-PEO-b-GRGDSG block copolymer, in which the peptide is linked through its N-terminus. PMID:12903721
Multiple peptide resistance factor (MprF)-mediated Resistance of Staphylococcus aureus against antimicrobial peptides coincides with a modulated peptide interaction with artificial membranes comprising lysyl-phosphatidylglycerol.
Andrä, Jörg; Goldmann, Torsten; Ernst, Christoph M; Peschel, Andreas; Gutsmann, Thomas
Modification of the membrane lipid phosphatidylglycerol (PG) of Staphylococcus aureus by enzymatic transfer of a l-lysine residue leading to lysyl-PG converts the net charge of PG from -1 to +1 and is thought to confer resistance to cationic antimicrobial peptides (AMPs). Lysyl-PG synthesis and translocation to the outer leaflet of the bacterial membrane are achieved by the membrane protein MprF. Consequently, mutants lacking a functional mprF gene are in particular vulnerable to the action of AMPs. Hence, we aim at elucidating whether and to which extent lysyl-PG modulates membrane binding, insertion, and permeabilization by various AMPs. Lysyl-PG was incorporated into artificial lipid bilayers, mimicking the cytoplasmic membrane of S. aureus. Moreover, we determined the activity of the peptides against a clinical isolate of S. aureus strain SA113 and two mutants lacking a functional mprF gene and visualized peptide-induced ultrastructural changes of bacteria by transmission electron microscopy. The studied peptides were: (i) NK-2, an α-helical fragment of mammalian NK-lysin, (ii) arenicin-1, a lugworm β-sheet peptide, and (iii) bee venom melittin. Biophysical data obtained by FRET spectroscopy, Fourier transform infrared spectroscopy, and electrical measurements with planar lipid bilayers were correlated with the biological activities of the peptides. They strongly support the hypothesis that peptide-membrane interactions are a prerequisite for eradication of S. aureus. However, degree and mode of modulation of membrane properties such as fluidity, capacitance, and conductivity were unique for each of the peptides. Altogether, our data support and underline the significance of lysyl-PG for S. aureus resistance to AMPs. PMID:21474443
Role of SbmA in the Uptake of Peptide Nucleic Acid (PNA)-Peptide Conjugates in E. coli
DEFF Research Database (Denmark)
Ghosal, Anubrata; Vitali, Ally; Stach, James E M; Nielsen, Peter E
-peptide conjugates had disruptions in the region of sbmA, a gene encoding an inner membrane peptide transporter. The wild type sensitivity to the PNA conjugates was re-established in the resistance mutants by complementation with sbmA. Furthermore, deletion of sbmA in E. coli AS19, a strain that is sensitive to...
Alternative Mechanisms for the Interaction of the Cell-Penetrating Peptides Penetratin and the TAT Peptide with Lipid Bilayers
Yesylevskyy, Semen; Marrink, Siewert-Jan; Mark, Alan E.
Cell-penetrating peptides (CPPs) have recently attracted much interest due to their apparent ability to penetrate cell membranes in an energy-independent manner. Here molecular-dynamics simulation techniques were used to study the interaction of two CPPs: penetratin and the TAT peptide with 1,2-Dipa
Study on peptide-peptide interaction using high-performance affinity chromatography and quartz crystal microbalance biosensor
Institute of Scientific and Technical Information of China (English)
LUO Jia; HUANG YanYan; XIONG ShaoXiang; LIU GuoQuan; ZHAO Rui
The specific interaction between sense and antisense peptides was studied by high-performance affinity chromatography (HPAC) and quartz crystal microbalance (QCM) biosensor. Fragment 1-14 of human interferon-β (hlFN-β) was chosen as sense peptide and its three antisense peptides (AS-IFN 1,AS-IFN 2, and AS-IFN 3) were designed according to the degeneracy of genetic codes. The affinity column was prepared with sense peptide as ligand and the affinity chromatographic behavior was evaluated. Glu-substituted antisense peptide (AS-IFN 3) showed the strongest binding to immobilized sense peptide at pH 7.5. A quartz crystal microbalance-flow injection analysis (QCM-FIA) system was introduced to investigate the recognition process in real-time. The equilibrium dissociation constants between sense peptide and AS-IFN 1, AS-IFN 2 and AS-IFN 3 measured 2.08×10-4, 1.31×10-4 and 2.22×10-5 mol/L, respectively. The mechanism study indicated that the specific recognition between sense peptide and AS-IFN 3 was due to sequence-dependent and multi-modal affinity interaction.
Metabolism of growth hormone releasing peptides.
Thomas, Andreas; Delahaut, Philippe; Krug, Oliver; Schänzer, Wilhelm; Thevis, Mario
New, potentially performance enhancing compounds have frequently been introduced to licit and illicit markets and rapidly distributed via worldwide operating Internet platforms. Developing fast analytical strategies to follow these new trends is one the most challenging issues for modern doping control analysis. Even if reference compounds for the active drugs are readily obtained, their unknown metabolism complicates effective testing strategies. Recently, a new class of small C-terminally amidated peptides comprising four to seven amino acid residues received considerable attention of sports drug testing authorities due to their ability to stimulate growth hormone release from the pituitary. The most promising candidates are the growth hormone releasing peptide (GHRP)-1, -2, -4, -5, -6, hexarelin, alexamorelin, and ipamorelin. With the exemption of GHRP-2, the entity of these peptides represents nonapproved pharmaceuticals; however, via Internet providers, all compounds are readily available. To date, only limited information on the metabolism of these substances is available and merely one metabolite for GHRP-2 is established. Therefore, a comprehensive in vivo (po and iv administration in rats) and in vitro (with human serum and recombinant amidase) study was performed in order to generate information on urinary metabolites potentially useful for routine doping controls. The urine samples from the in vivo experiments were purified by mixed-mode cation-exchange solid-phase extraction and analyzed by ultrahigh-performance liquid chromatography (UHPLC) separation followed by high-resolution/high-accuracy mass spectrometry. Combining the high resolution power of a benchtop Orbitrap mass analyzer for the first metabolite screening and the speed of a quadrupole/time-of-flight (Q-TOF) instrument for identification, urinary metabolites were screened by means of a sensitive full scan analysis and subsequently confirmed by high-accuracy product ion scan experiments. Two
Enhanced cellular delivery of cell-penetrating peptide-peptide nucleic acid conjugates by photochemical internalization
DEFF Research Database (Denmark)
Shiraishi, Takehiko; Nielsen, Peter E
Cell-penetrating peptides (CPPs) have been widely used for a cellular delivery of biologically relevant cargoes including antisense peptide nucleic acids (PNAs). Although chemical conjugation of PNA to a variety of CPPs significantly improves the cellular uptake of the PNAs, bioavailability...... (antisense activity) is still limited by endocytotic entrapment. We have shown that this low bioavailability can be greatly improved by combining CPP-PNA conjugate administration with a photochemical internalization technique using photosensitizers such as aluminum phthalocyanine (AlPcS(2a)) or...... cellular efficacy of CPP conjugates were evaluated by measuring luciferase activity as a result of splicing correction and was also confirmed by RT-PCR analysis of luciferase pre-mRNA....
Electrical transport properties of peptide nanotubes coated with gold nanoparticles via peptide-induced biomineralization
International Nuclear Information System (INIS)
We present temperature dependent electrical transport measurements of peptide nanotube devices coated with monodisperse arrays of gold nanoparticles (AuNP). As the temperature is lowered, the current-voltage (I-V) characteristics become increasingly nonlinear and below 20 K conduction only occurs above a threshold voltage VT. The current follows the scaling behavior I∝[(V-VT)/VT]α for V > VT with α ∼ 2.5 signifying two-dimensional (2D) charge transport. The temperature dependence of the resistance shows thermally activated behavior with an activation energy of 18.2 meV corresponding to the sequential tunneling of charges through 6 nm monodispersed AuNP arrays grown on a peptide surface.
Applications and Challenges for Use of Cell-Penetrating Peptides as Delivery Vectors for Peptide and Protein Cargos
DEFF Research Database (Denmark)
Kristensen, Mie; Birch, Ditlev; Mørck Nielsen, Hanne
-penetrating peptides (CPPs) constitute a promising tool and have shown applications for peptide and protein delivery into cells as well as across various epithelia and the blood-brain barrier (BBB). CPP-mediated delivery of peptides and proteins may be pursued via covalent conjugation of the CPP to the cargo peptide...... or protein or via physical complexation obtained by simple bulk-mixing of the CPP with its cargo. Both approaches have their pros and cons, and which is the better choice likely relates to the physicochemical properties of the CPP and its cargo as well as the route of administration, the specific...... barrier and the target cell. Besides the physical barrier, a metabolic barrier must be taken into consideration when applying peptide-based delivery vectors, such as the CPPs, and stability-enhancing strategies are commonly employed to prolong the CPP half-life. The mechanisms by which CPPs translocate...
Tidbits for the synthesis of bis(2-sulfanylethyl)amido (SEA) polystyrene resin, SEA peptides and peptide thioesters.
Ollivier, Nathalie; Raibaut, Laurent; Blanpain, Annick; Desmet, Rémi; Dheur, Julien; Mhidia, Reda; Boll, Emmanuelle; Drobecq, Hervé; Pira, Silvain L; Melnyk, Oleg
Protein total chemical synthesis enables the atom-by-atom control of the protein structure and therefore has a great potential for studying protein function. Native chemical ligation of C-terminal peptide thioesters with N-terminal cysteinyl peptides and related methodologies are central to the field of protein total synthesis. Consequently, methods enabling the facile synthesis of peptide thioesters using Fmoc-SPPS are of great value. Herein, we provide a detailed protocol for the preparation of bis(2-sulfanylethyl)amino polystyrene resin as a starting point for the synthesis of C-terminal bis(2-sulfanylethyl)amido peptides and of peptide thioesters derived from 3-mercaptopropionic acid. PMID:24254655
Evaluation of carrier ampholyte-based capillary electrophoresis for separation of peptides and peptide mimetics
Czech Academy of Sciences Publication Activity Database
Koval, Dušan; Busnel, J. M.; Hlaváček, Jan; Jiráček, Jiří; Kašička, Václav; Peltre, G.
Roč. 29, č. 18 (2008), s. 3759-3767. ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA203/06/1044; GA ČR GA203/06/1272; GA ČR GA203/08/1428 Institutional research plan: CEZ:AV0Z40550506 Keywords : capillary electrophoresis * carrier ampholytes * peptides Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.509, year: 2008
Antibacterial Peptide Nucleic Acid-Antimicrobial Peptide (PNA-AMP) Conjugates
DEFF Research Database (Denmark)
Hansen, Anna Mette; Bonke, Gitte; Larsen, Camilla Josephine; Yavari, Niloofar; Nielsen, Peter E.; Franzyk, Henrik
)-Tat48-60, BF-2A-RXR, and drosocin-RXR are capable of transporting PNA effectively into E. coli (MICs of 1-4 μM). Importantly, presence of the inner-membrane peptide transporter SbmA was not required for antibacterial activity of PNA-AMP conjugates containing Pep-1-K, KLW-9,13-a, or drosocin-RXR (MICs...
Kidney function and peptide receptor radionuclide therapy (PRRT); Nierenfunktion und Peptid-Rezeptor-Radionuklid-Therapie (PRRT)
Energy Technology Data Exchange (ETDEWEB)
Prasad, Vikas [Universitaetsmedizin Berlin (Germany). Klinik fuer Nuklearmedizin
The peptide receptor radionuclide therapy (PRRT) using 90-Yttrium or 177-Lutetium labelled somatostatin analog is one of the systemic antitumor therapy options for gastroenteropancreatic neuroendocrine tumors. These radiolabeled somatostatin analogues get excreted primarily through the kidneys making it the critical organ for PRRT. Terminal kidney insufficiency has been reported with {sup 90}Y-DOTATOC. This manuscript tries to bring together the actual facts related to the PRRT related nephrotoxicity and the methods to reduce the kidney damage. (orig.)
Some arachnidan peptides with potential medical application
Directory of Open Access Journals (Sweden)
ME De Lima
Full Text Available The search for new active drugs that can alleviate or cure different diseases is a constant challenge to researchers in the biological area and to the pharmaceutical industry. Historically, research has focused on the study of substances from plants. More recently, however, animal venoms have been attracting attention and studies have been successful in addressing treatment of accidents. Furthermore, venoms and their toxins have been considered good tools for prospecting for new active drugs or models for new therapeutic drugs. In this review, we discuss some possibilities of using different toxins, especially those from arachnid venoms, which have shown some potential application in diseases involving pain, hypertension, epilepsy and erectile dysfunction. A new generation of drugs is likely to emerge from peptides, including those found in animal venoms.
Crystallizing Transmembrane Peptides in Lipidic Mesophases
Energy Technology Data Exchange (ETDEWEB)
Höfer, Nicole; Aragão, David; Caffrey, Martin (Trinity)
Structure determination of membrane proteins by crystallographic means has been facilitated by crystallization in lipidic mesophases. It has been suggested, however, that this so-called in meso method, as originally implemented, would not apply to small protein targets having {le}4 transmembrane crossings. In our study, the hypothesis that the inherent flexibility of the mesophase would enable crystallogenesis of small proteins was tested using a transmembrane pentadecapeptide, linear gramicidin, which produced structure-grade crystals. This result suggests that the in meso method should be considered as a viable means for high-resolution structure determination of integral membrane peptides, many of which are predicted to be coded for in the human genome.
Peptides whose uptake by cells is controllable
Energy Technology Data Exchange (ETDEWEB)
Jiang, Tao; Olson, Emilia S.; Whitney, Michael; Tsien, Roger
A generic structure for the peptides of the present invention includes A-X-B-C, where C is a cargo moiety, the B portion includes basic amino acids, X is a cleavable linker sequence, and the A portion includes acidic amino acids. The intact structure is not significantly taken up by cells; however, upon extracellular cleavage of X, the B-C portion is taken up, delivering the cargo to targeted cells. Cargo may be, for example, a contrast agent for diagnostic imaging, a chemotherapeutic drug, or a radiation-sensitizer for therapy. X may be cleaved extracellularly or intracellularly. The molecules of the present invention may be linear, cyclic, branched, or have a mixed structure.
Peptides whose uptake by cells is controllable
Energy Technology Data Exchange (ETDEWEB)
Jiang, Tao; Tsien, Roger Y
A generic structure for the peptides of the present invention includes A-X-B-C, where C is a cargo moiety, the B portion includes basic amino acids, X is a cleavable linker sequence, and the A portion includes acidic amino acids. The intact structure is not significantly taken up by cells; however, upon extracellular cleavage of X, the B-C portion is taken up, delivering the cargo to targeted cells. Cargo may be, for example, a contrast agent for diagnostic imaging, a chemotherapeutic drug, or a radiation-sensitizer for therapy. Cleavage of X allows separation of A from B, unmasking the normal ability of the basic amino acids in B to drag cargo C into cells near the cleavage event. X is cleaved extracellularly, preferably under physiological conditions. D-amino acids are preferred for the A and B portions, to minimize immunogenicity and nonspecific cleavage by background peptidases or proteases.
Peptide receptor radionuclide therapy of neuroendocrine tumours.
Brabander, Tessa; Teunissen, Jaap J M; Van Eijck, Casper H J; Franssen, Gaston J H; Feelders, Richard A; de Herder, Wouter W; Kwekkeboom, Dik J
In the past decades, the number of neuroendocrine tumours that are detected is increasing. A relative new and promising therapy for patients with metastasised or inoperable disease is peptide receptor radionuclide therapy (PRRT). This therapy involves an infusion of somatostatin analogues linked to radionuclides like Yttrium-90 or Lutetium-177. Objective response rates are reported in 15-35%. Response rates may vary between type of tumour and radionuclide. Besides the objective response rate, overall survival and progression free survival increase significantly. Also, the quality of life improves as well. Serious side-affects are rare. PRRT is usually well tolerated, also in patients with extensive metastasised disease. Recent studies combined PRRT with other types of therapies. Unfortunately no randomised trials comparing these strategies are available. In the future, more research is needed to evaluate the best therapy combinations or sequence of therapies. PMID:26971847
Coexistence of peptides with classical neurotransmitters.
Hökfelt, T; Millhorn, D; Seroogy, K; Tsuruo, Y; Ceccatelli, S; Lindh, B; Meister, B; Melander, T; Schalling, M; Bartfai, T
In the present article the fact is emphasized that neuropeptides often are located in the same neurons as classical transmitters such as acetylcholine, 5-hydroxy-tryptamine, catecholamines, gamma-aminobutyric acid (GABA) etc. This raises the possibility that neurons produce, store and release more than one messenger molecule. The exact functional role of such coexisting peptides is often difficult to evaluate, especially in the central nervous system. In the periphery some studies indicate apparently meaningful interactions of different types with the classical transmitter, but other types of actions including trophic effects have been observed. More recently it has been shown that some neurons contain more than one classical transmitter, e.g. 5-HT plus GABA, further underlining the view that transfer of information across synapses may be more complex than perhaps hitherto assumed. PMID:2885215
Micro-structured peptide surfaces for the detection of high-affinity peptide-receptor interactions in living cells.
Lipp, Anna-Maria; Ji, Bozhi; Hager, Roland; Haas, Sandra; Schweiggl, Simone; Sonnleitner, Alois; Haselgrübler, Thomas
Peptide ligands have great potential as selective agents for diagnostic imaging and therapeutic targeting of human cancers. A number of high-throughput assays for screening potential candidate peptides have been developed. Although these screening assays are indispensable for the identification of peptide ligands at a large scale, it is crucial to validate peptide binding and selectivity for targeted receptors in a live-cell context. For testing high-affinity peptide-receptor interactions in the plasma membrane of living cells, we developed cell-resistant, micro-structured glass surfaces with high-density and high-contrast peptide features. Cell adhesion and recruitment of fluorescent receptors to micro-patterned peptides in the live-cell membrane were evaluated by reflection interference contrast (RIC) and total internal reflection (TIRF) microscopy, respectively. To demonstrate both the specificity and modularity of the assay, co-patterning of fluorescent receptors with three different immobilized micro-structured ligands was shown: first, interaction of green fluorescent protein (GFP)-tagged epidermal growth factor (EGF) receptor expressed in Jurkat cells with immobilized EGF was detected and quantified. Second, using Jurkat cells, we demonstrated specific interaction of yellow fluorescent protein (YFP)-tagged β3 integrin with c(RGDfK) peptide. Third, we identified indirect recruitment of GFP-tagged α5 integrin to an 11-mer peptide. In summary, our results show that the developed micro-structured surfaces are a useful tool for the validation and quantification of peptide-receptor interactions in their natural cellular environment. PMID:26210593
Sifuvirtide, a potent HIV fusion inhibitor peptide
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Wang, Rui-Rui; Yang, Liu-Meng; Wang, Yun-Hua [Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223 (China); Pang, Wei [Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223 (China); Department of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080 (China); Tam, Siu-Cheung [Department of Physiology, Chinese University of Hong Kong, Shatin, N.T., Hong Kong (China); Tien, Po [Department of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080 (China); Zheng, Yong-Tang, E-mail: email@example.com [Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223 (China)
Enfuvirtide (ENF) is currently the only FDA approved HIV fusion inhibitor in clinical use. Searching for more drugs in this category with higher efficacy and lower toxicity seems to be a logical next step. In line with this objective, a synthetic peptide with 36 amino acid residues, called Sifuvirtide (SFT), was designed based on the crystal structure of gp41. In this study, we show that SFT is a potent anti-HIV agent with relatively low cytotoxicity. SFT was found to inhibit replication of all tested HIV strains. The effective concentrations that inhibited 50% viral replication (EC{sub 50}), as determined in all tested strains, were either comparable or lower than benchmark values derived from well-known anti-HIV drugs like ENF or AZT, while the cytotoxic concentrations causing 50% cell death (CC{sub 50}) were relatively high, rendering it an ideal anti-HIV agent. A GST-pull down assay was performed to confirm that SFT is a fusion inhibitor. Furthermore, the activity of SFT on other targets in the HIV life cycle was also investigated, and all assays showed negative results. To further understand the mechanism of action of HIV peptide inhibitors, resistant variants of HIV-1{sub IIIB} were derived by serial virus passage in the presence of increasing doses of SFT or ENF. The results showed that there was cross-resistance between SFT and ENF. In conclusion, SFT is an ideal anti-HIV agent with high potency and low cytotoxicity, but may exhibit a certain extent of cross-resistance with ENF.
Sifuvirtide, a potent HIV fusion inhibitor peptide
International Nuclear Information System (INIS)
Enfuvirtide (ENF) is currently the only FDA approved HIV fusion inhibitor in clinical use. Searching for more drugs in this category with higher efficacy and lower toxicity seems to be a logical next step. In line with this objective, a synthetic peptide with 36 amino acid residues, called Sifuvirtide (SFT), was designed based on the crystal structure of gp41. In this study, we show that SFT is a potent anti-HIV agent with relatively low cytotoxicity. SFT was found to inhibit replication of all tested HIV strains. The effective concentrations that inhibited 50% viral replication (EC50), as determined in all tested strains, were either comparable or lower than benchmark values derived from well-known anti-HIV drugs like ENF or AZT, while the cytotoxic concentrations causing 50% cell death (CC50) were relatively high, rendering it an ideal anti-HIV agent. A GST-pull down assay was performed to confirm that SFT is a fusion inhibitor. Furthermore, the activity of SFT on other targets in the HIV life cycle was also investigated, and all assays showed negative results. To further understand the mechanism of action of HIV peptide inhibitors, resistant variants of HIV-1IIIB were derived by serial virus passage in the presence of increasing doses of SFT or ENF. The results showed that there was cross-resistance between SFT and ENF. In conclusion, SFT is an ideal anti-HIV agent with high potency and low cytotoxicity, but may exhibit a certain extent of cross-resistance with ENF.
Rationale for the use of radiolabelled peptides in diagnosis and therapy
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Koopmans, K.P. [Martini Hospital, Department of Radiology and Nuclear Medicine, Groningen (Netherlands); Glaudemans, A.W.J.M. [University of Groningen, Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, Groningen (Netherlands)
Nuclear medicine techniques are becoming more important in imaging oncological and infectious diseases. For metabolic imaging of these diseases, antibody and peptide imaging are currently used. In recent years peptide imaging has become important, therefore the rationale for the use of peptide imaging is described in this article. Criteria for a successful peptide tracer are a high target specificity, a high binding affinity, a long metabolic stability and a high target-to-background ratio. Tracer internalization is also beneficial. For oncological imaging, many tracers are available, most originating from regulatory peptides, but penetrating peptides are also being developed. Peptides for imaging inflammatory and infectious diseases include regulatory peptides, antimicrobial peptides and others. In conclusion, for the imaging of oncological, inflammatory and infectious diseases, many promising peptides are being developed. The ideal peptide probe is characterized by rapid and specific target localization and binding with a high tumour-to-background ratio. (orig.)
Insulinotropic action of bombesin-like peptides mediated by gastrin-releasing peptide receptors in steers.
Zhao, H Q; Yao, G; Yannaing, S; ThanThan, S; Kuwayama, H
The present study characterizes the receptor that mediates the insulinotropic action of bombesin-like peptides (BLP) in ruminants. Eight Holstein steers were randomly and intravenously injected with synthetic bovine gastrin-releasing peptide (GRP; 0.9 nmol/kg BW), neuromedin B (NMB; 0.9 nmol/kg BW), or neuromedin C (NMC; 0.9 nmol/kg BW), each alone or combined with the antagonist of GRP receptors N-acetyl-GRP-OCHCH (N-GRP-EE; 22.5 nmol/kg BW) or the antagonist of GH secretagogue receptor type 1a (GHS-R1a) [D-Lys]-GHRP-6 (21.5 nmol/kg BW). Blood samples were collected at -10, 0 (just before injection), 5, 10, 15, 20, 30, 45, 60, 75, and 90 min relative to injection time. Levels of injected peptides, insulin, and glucose in plasma were analyzed. Results showed that the peak of insulin levels was seen at 5 min after injection of NMC or GRP. Plasma glucose was observed in 2 phases; a significant rise followed a remarkable fall after NMC or GRP administration compared with injection of the vehicle ( 0.05). These results indicated that the insulinotropic action of BLP is mediated by GRP receptors but not through a ghrelin/GHS-R1a pathway and that BLP may be involved in the regulation of glucose homeostasis in ruminants. PMID:26812312
Signal peptide of eosinophil cationic protein is toxic to cells lacking signal peptide peptidase
International Nuclear Information System (INIS)
Eosinophil cationic protein (ECP) is a toxin secreted by activated human eosinophils. The properties of mature ECP have been well studied but those of the signal peptide of ECP (ECPsp) are not clear. In this study, several chimeric proteins containing N-terminal fusion of ECPsp were generated, and introduced into Escherichia coli, Pichia pastoris, and human epidermoid carcinoma cell line A431 to study the function of ECPsp. We found that expression of ECPsp chimeric proteins inhibited the growth of E. coli and P. pastoris but not A431 cells. Primary sequence analysis and in vitro transcription/translation of ECPsp have revealed that it is a potential substrate for human signal peptide peptidase (hSPP), an intramembrane protease located in endoplasmic reticulum. In addition, knockdown of the hSPP mRNA expression in ECPsp-eGFP/A431 cells caused the growth inhibitory effect, whereas complementally expression of hSPP in P. pastoris system rescued the cell growth. Taken together, we have demonstrated that ECPsp is a toxic signal peptide, and expression of hSPP protects the cells from growth inhibition
Syntactomer Peptide Assembly on Deformable Silicone Elastomer Surfaces
Albert, Julie N. L.; Genzer, Jan
Surfaces of biocompatible poly(vinylmethylsiloxane) (PVMS) networks can be functionalized readily through modification of pendent vinyl groups. In this work, we also took advantage of network elasticity to examine how the conformation of surface-grafted peptides depended on their grafting density (i.e., the areal density of peptides). PVMS networks were cross-linked via reactive end groups, leaving the pendent vinyl groups available for peptide attachment via a carboxylic acid terminated thiol linker. To control grafting density, the networks were stretched uniaxially up to ~30% strain during the attachment of the thiol linker (via thiol-ene click chemistry) and the peptide (via sulfo-NHS/EDC coupling chemistry). After deposition, the strain was released. The resultant peptide-modified PVMS networks were imaged using scanning probe microscopy. The specific peptides of interest are called ``syntactomers'' because they are made up of repeating amino acid sequences much like a polymer is made up of repeating monomer units. In solution, these peptides display interesting pH-sensitive LCST and UCST phase behaviors that may impart surfaces with pH- and temperature-responsiveness in addition to biocompatibility.
Design of nanostructures based on aromatic peptide amphiphiles.
Fleming, Scott; Ulijn, Rein V
Aromatic peptide amphiphiles are gaining popularity as building blocks for the bottom-up fabrication of nanomaterials, including gels. These materials combine the simplicity of small molecules with the versatility of peptides, with a range of applications proposed in biomedicine, nanotechnology, food science, cosmetics, etc. Despite their simplicity, a wide range of self-assembly behaviours have been described. Due to varying conditions and protocols used, care should be taken when attempting to directly compare results from the literature. In this review, we rationalise the structural features which govern the self-assembly of aromatic peptide amphiphiles by focusing on four segments, (i) the N-terminal aromatic component, (ii) linker segment, (iii) peptide sequence, and (iv) C-terminus. It is clear that the molecular structure of these components significantly influences the self-assembly process and resultant supramolecular architectures. A number of modes of assembly have been proposed, including parallel, antiparallel, and interlocked antiparallel stacking conformations. In addition, the co-assembly arrangements of aromatic peptide amphiphiles are reviewed. Overall, this review elucidates the structural trends and design rules that underpin the field of aromatic peptide amphiphile assembly, paving the way to a more rational design of nanomaterials based on aromatic peptide amphiphiles. PMID:25199102
Novel inhibitor cystine knot peptides from Momordica charantia.
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Wen-Jun He
Full Text Available Two new peptides, MCh-1 and MCh-2, along with three known trypsin inhibitors (MCTI-I, MCTI-II and MCTI-III, were isolated from the seeds of the tropical vine Momordica charantia. The sequences of the peptides were determined using mass spectrometry and NMR spectroscopy. Using a strategy involving partial reduction and stepwise alkylation of the peptides, followed by enzymatic digestion and tandem mass spectrometry sequencing, the disulfide connectivity of MCh-1 was elucidated to be CysI-CysIV, CysII-CysV and CysIII-CysVI. The three-dimensional structures of MCh-1 and MCh-2 were determined using NMR spectroscopy and found to contain the inhibitor cystine knot (ICK motif. The sequences of the novel peptides differ significantly from peptides previously isolated from this plant. Therefore, this study expands the known peptide diversity in M. charantia and the range of sequences that can be accommodated by the ICK motif. Furthermore, we show that a stable two-disulfide intermediate is involved in the oxidative folding of MCh-1. This disulfide intermediate is structurally homologous to the proposed ancestral fold of ICK peptides, and provides a possible pathway for the evolution of this structural motif, which is highly prevalent in nature.
Peptide Arrays for Binding Studies of E3 Ubiquitin Ligases.
Klecker, Maria; Dissmeyer, Nico
The automated SPOT (synthetic peptide arrays on membrane support technique) synthesis technology has entrenched as a rapid and robust method to generate peptide libraries on cellulose membrane supports. The synthesis method is based on conventional Fmoc chemistry building up peptides with free N-terminal amino acids starting at their cellulose-coupled C-termini. Several hundreds of peptide sequences can be assembled with this technique on one membrane comprising a strong binding potential due to high local peptide concentrations. Peptide orientation on SPOT membranes qualifies this array type for assaying substrate specificities of N-recognins, the recognition elements of the N-end rule pathway of targeted protein degradation (NERD). Pioneer studies described binding capability of mammalian and yeast enzymes depending on a peptide's N-terminus. SPOT arrays have been successfully used to describe substrate specificity of N-recognins which are the recognition elements of the N-end rule pathway of targeted protein degradation (NERD). Here, we describe the implementation of SPOT binding assays with focus on the identification of N-recognin substrates, applicable also for plant NERD enzymes. PMID:27424747
Peptide adsorption on the hydrophobic surface: A free energy perspective
Sheng, Yuebiao; Wang, Wei; Chen, P.
Protein adsorption is a very attractive topic which relates to many novel applications in biomaterials, biotechnology and nanotechnology. Ionic complementary peptides are a group of novel nano-biomaterials with many biomedical applications. In this work, molecular dynamics simulations of the ionic-complementary peptide EAK16-II on a hydrophobic graphite surface were performed under neutral, acidic and basic solution conditions. Adsorption free energy contour maps were obtained by analyzing the dynamical trajectories. Hydrophobic interactions were found to govern the adsorption of the first peptide molecule, and both hydrophobic and electrostatic interactions contributed to the adsorption of the second peptide molecule. Especially under acidic and basic solution conditions, interplay existed among chain-chain hydrophobic, chain-surface hydrophobic and chain-chain electrostatic interactions during the adsorption of the second peptide molecule. Non-charged residues were found to lie on the graphite surface, while charged residue side-chains oriented towards the solution after the peptide deposited on the surface. These results provide a basis for understanding peptide adsorption on the hydrophobic surface under different solution conditions, which is useful for novel applications such as bioactive implant devices and drug delivery material design.
Injectable polymer microspheres enhance immunogenicity of a contraceptive peptide vaccine.
Cui, Chengji; Stevens, Vernon C; Schwendeman, Steven P
Advanced contraceptive peptide vaccines suffer from the unavailability of adjuvants capable of enhancing the antibody response with acceptable safety. We sought to overcome this limitation by employing two novel poly(lactic-co-glycolic acid) (PLGA) microsphere formulations to deliver a synthetic human chorionic gonadotropin (hCG) peptide antigen co-synthesized with a T-cell epitope from tetanus toxoid (TT), C-TT2-CTP35: surface-conjugated immunogen to induce phagocytosis; and encapsulated peptide to provide a depot effect, with MgCO(3) co-encapsulated in the polymer to neutralize acidity from the biodegrading PLGA polyester. A single immunization of encapsulated peptide in rabbits elicited a stronger antibody response with equivalent duration relative to a positive control--three injections of the peptide administered in a squalene-based water-in-oil emulsion. Surface-conjugated peptide was less effective but enhanced antibody levels at 1/5 the dose, relative to soluble antigen. Most remarkable and unexpected was the finding that co-encapsulation of base was essential to attain the powerful adjuvant effect of the PLGA-MgCO(3) system, as the MgCO(3)-free microspheres were completely ineffective. A promising contraceptive hCG peptide vaccine with acceptable side effects (i.e., local tissue reactions) was achieved by minimizing PLGA and MgCO(3) doses, without significantly affecting antibody response. PMID:16996662
Drug carriers for the delivery of therapeutic peptides.
Du, Alice W; Stenzel, Martina H
Peptides take on an increasingly important role as therapeutics in areas including diabetes, oncology, and metabolic, cardiovascular, and infectious diseases. In addition, many peptides such as insulin have been employed for many years. A challenge in the administration of peptide drugs is their often low hydrolytic stability, as well as other problems that are common to any drug treatment such as systemic distribution. There is a significant attention in the literature of protein drugs and their delivery strategies, but not many overviews are specifically dedicated to peptides. In this review, the different approaches to deliver peptides have been summarized where the focus is only on drug carriers based on organic materials. Initial discussion is on different methods of polymer-peptide conjugation before being followed by physical encapsulation techniques, which is divided into surfactant-based techniques and polymer carriers. Surfactant-based techniques are dominated by liposome, microemulsions and solid-lipid nanoparticles. The field widens further in the polymer field. The delivery of peptides has been enhanced using polymer-decorated liposomes, solid microspheres, polyelectrolyte complex, emulsions, hydrogels, and injectable polymers. The aim of this article is to give the reader an overview over the different types of carriers. PMID:24661025
Cellular and physiological effects of C-peptide.
Hills, Claire E; Brunskill, Nigel J
In recent years, accumulating evidence indicates a biological function for proinsulin C-peptide. These results challenge the traditional view that C-peptide is essentially inert and only useful as a surrogate marker of insulin release. Accordingly, it is now clear that C-peptide binds with high affinity to cell membranes, probably to a pertussis-toxin-sensitive G-protein-coupled receptor. Subsequently, multiple signalling pathways are potently and dose-dependently activated in multiple cell types by C-peptide with the resulting activation of gene transcription and altered cell phenotype. In diabetic animals and Type 1 diabetic patients, short-term studies indicate that C-peptide also enhances glucose disposal and metabolic control. Furthermore, results derived from animal models and clinical studies in Type 1 diabetic patients suggest a salutary effect of C-peptide in the prevention and amelioration of diabetic nephropathy and neuropathy. Therefore a picture of Type 1 diabetes as a dual-hormone-deficiency disease is developing, suggesting that the replacement of C-peptide alongside insulin should be considered in its management. PMID:19243312
Prediction of cell-penetrating peptides with feature selection techniques.
Tang, Hua; Su, Zhen-Dong; Wei, Huan-Huan; Chen, Wei; Lin, Hao
Cell-penetrating peptides are a group of peptides which can transport different types of cargo molecules such as drugs across plasma membrane and have been applied in the treatment of various diseases. Thus, the accurate prediction of cell-penetrating peptides with bioinformatics methods will accelerate the development of drug delivery systems. The study aims to develop a powerful model to accurately identify cell-penetrating peptides. At first, the peptides were translated into a set of vectors with the same dimension by using dipeptide compositions. Secondly, the Analysis of Variance-based technique was used to reduce the dimension of the vector and explore the optimized features. Finally, the support vector machine was utilized to discriminate cell-penetrating peptides from non-cell-penetrating peptides. The five-fold cross-validated results showed that our proposed method could achieve an overall prediction accuracy of 83.6%. Based on the proposed model, we constructed a free webserver called C2Pred (http://lin.uestc.edu.cn/server/C2Pred). PMID:27291150
Synthetic peptides with antigenic specificity for bacterial toxins.
Sela, M; Arnon, R; Jacob, C O
The attachment of a diphtheria toxin-specific synthetic antigenic determinant and a synthetic adjuvant to a synthetic polymeric carrier led to production of a totally synthetic macromolecule which provoked protective antibodies against diphtheria when administered in aqueous solution. When peptides related to the B subunit of cholera toxin were synthesized and attached to tetanus toxoid, antibodies produced against the conjugate reacted in some but not all cases with intact cholera toxin and (especially with peptide CTP 3, residues 50-64) neutralized toxin reactivity, as tested by permeability in rabbit skin, fluid accumulation in ligated small intestinal loops and adenylate cyclase activation. Polymerization of the peptide without any external carrier, or conjugation with the dipalmityl lysine group, had as good an effect in enhancing the immune response as its attachment to tetanus toxoid. Prior exposure to the carrier suppressed the immune response to the epitope attached to it, whereas prior exposure to the synthetic peptide had a good priming effect when the intact toxin was given; when two different peptides were attached to the same carrier, both were expressed. Antisera against peptide CTP 3 were highly cross-reactive with the heat-labile toxin of Escherichia coli and neutralized it to the same extent as cholera toxin, which is not surprising in view of the great homology between the two proteins. A synthetic oligonucleotide coding for CTP 3 has been used to express the peptide in a form suitable for immunization. It led to a priming effect against the intact cholera toxin. PMID:2426052
Natural antimicrobial peptides as promising anti-HIV candidates
Wang, Guangshun
Human immunodeficiency virus type 1 (HIV-1) infection remains to be one of the major global health problems. It is thus necessary to identify novel therapeutic molecules to combat HIV-1. Natural antimicrobial peptides (AMPs) have been recognized as promising templates for developing topical microbicides. This review systematically discusses over 80 anti-HIV peptides annotated in the antimicrobial peptide database (http://aps.unmc.edu/AP). Such peptides have been discovered from bacteria, plants, and animals. Examples include gramicidin and bacteriocins from bacteria, cyclotides from plants, melittins and cecropins from insects, piscidins from fish, ascaphins, caerins, dermaseptins, esculentins, and maximins from amphibians, and cathelicidins and defensins from vertebrates. These peptides appear to work by different mechanisms and could block viral entry in multiple ways. As additional advantages, such anti-HIV peptides may possess other desired features such as antibacterial, antiparasital, spermicidal, and anticancer activity. With continued optimization of peptide stability, production, formulation and delivery methods, it is anticipated that some of these compounds may eventually become new anti-HIV drugs. PMID:26834391
Graphene Symmetry Amplified by Designed Peptide Self-Assembly.
Mustata, Gina-Mirela; Kim, Yong Ho; Zhang, Jian; DeGrado, William F; Grigoryan, Gevorg; Wanunu, Meni
We present a strategy for designed self-assembly of peptides into two-dimensional monolayer crystals on the surface of graphene and graphite. As predicted by computation, designed peptides assemble on the surface of graphene to form very long, parallel, in-register β-sheets, which we call β-tapes. Peptides extend perpendicularly to the long axis of each β-tape, defining its width, with hydrogen bonds running along the axis. Tapes align on the surface to create highly regular microdomains containing 4-nm pitch striations. Moreover, in agreement with calculations, the atomic structure of the underlying graphene dictates the arrangement of the β-tapes, as they orient along one of six directions defined by graphene's sixfold symmetry. A cationic-assembled peptide surface is shown here to strongly adhere to DNA, preferentially orienting the double helix along β-tape axes. This orientational preference is well anticipated from calculations, given the underlying peptide layer structure. These studies illustrate how designed peptides can amplify the Ångstrom-level atomic symmetry of a surface onto the micrometer scale, further imparting long-range directional order onto the next level of assembly. The remarkably stable nature of these assemblies under various environmental conditions suggests applications in enzymelike catalysis, biological interfaces for cellular recognition, and two-dimensional platforms for studying DNA-peptide interactions. PMID:27276268
Angiotensin I converting enzyme inhibitory peptide extracted from freshwater zooplankton.
Lee, Jung Kwon; Lee, Min-Su; Park, Heum Gi; Kim, Se-Kwon; Byun, Hee-Guk
In this study, hydrolysates obtained from the freshwater rotifer Brachionus calyciflonus were investigated for angiotensin I converting enzyme (ACE) inhibitory peptides. Freshwater rotifer protein was hydrolyzed using six separate enzymes in a batch reactor. The peptic hydrolysate had the highest ACE inhibitory activity compared to the other hydrolysates. The highest ACE inhibitory peptide was separated using Sephadex G-25 column chromatography and high-performance liquid chromatography on a C18 column. The 50% inhibitory concentration (IC(50)) value of purified ACE inhibitory peptide was 40.01 microg/mL. ACE inhibitory peptide was identified as being seven amino acid residues of Ala-Gln-Gly-Glu-Arg-His-Arg by N-terminal amino acid sequence analysis. The IC(50) value of purified ACE inhibitory peptide was 47.1 microM, and Lineweaver-Burk plots suggested that the peptide purified from rotifer protein acts as a competitive inhibitor against ACE. The results of this study suggest that peptides derived from freshwater rotifers may be beneficial as antihypertension compounds in functional foods or as pharmaceuticals. PMID:20170338
Transmembrane transport of peptide type compounds: prospects for oral delivery
Lipka, E.; Crison, J.; Amidon, G. L.
Synthesis and delivery of potential therapeutic peptides and peptidomimetic compounds has been the focus of intense research over the last 10 years. While it is widely recognized that numerous limitations apply to oral delivery of peptides, some of the limiting factors have been addressed and their mechanisms elucidated, which has lead to promising strategies. This article will briefly summarize the challenges, results and current approaches of oral peptide delivery and give some insight on future strategies. The barriers determining peptide bioavailability after oral administration are intestinal membrane permability, size limitations, intestinal and hepatic metabolism and in some cases solubility limitations. Poor membrane permeabilities of hydrophilic peptides might be overcome by structurally modifying the compounds, thus increasing their membrane partition characteristics and/or their affinity to carrier proteins. Another approach is the site-specific delivery of the peptide to the most permeable parts of the intestine. The current view on size limitation for oral drug delivery has neglected partition considerations. Recent studies suggest that compounds with a molecular weight up to 4000 might be significantly absorbed, assuming appropriate partition behavior and stability. Metabolism, probably the most significant factor in the absorption fate of peptides, might be controlled by coadministration of competitive enzyme inhibitors, structural modifications and administration of the compound as a well absorbed prodrug that is converted into the therapeutically active agent after its absorption. For some peptides poor solubility might present a limitation to oral absorption, an issue that has been addressed by mechanistically defining and therefore improving formulation parameters. Effective oral peptide delivery requires further development in understanding these complex mechanisms in order to maximize the therapeutic potential of this class of compounds.
Solvation free energies of alanine peptides: the effect of flexibility.
Kokubo, Hironori; Harris, Robert C; Asthagiri, Dilipkumar; Pettitt, B Montgomery
The electrostatic (ΔGel), van der Waals cavity-formation (ΔGvdw), and total (ΔG) solvation free energies for 10 alanine peptides ranging in length (n) from 1 to 10 monomers were calculated. The free energies were computed both with fixed, extended conformations of the peptides and again for some of the peptides without constraints. The solvation free energies, ΔGel, and components ΔGvdw, and ΔG, were found to be linear in n, with the slopes of the best-fit lines being γel, γvdw, and γ, respectively. Both γel and γ were negative for fixed and flexible peptides, and γvdw was negative for fixed peptides. That γvdw was negative was surprising, as experimental data on alkanes, theoretical models, and MD computations on small molecules and model systems generally suggest that γvdw should be positive. A negative γvdw seemingly contradicts the notion that ΔGvdw drives the initial collapse of the protein when it folds by favoring conformations with small surface areas. When we computed ΔGvdw for the flexible peptides, thereby allowing the peptides to assume natural ensembles of more compact conformations, γvdw was positive. Because most proteins do not assume extended conformations, a ΔGvdw that increases with increasing surface area may be typical for globular proteins. An alternative hypothesis is that the collapse is driven by intramolecular interactions. We find few intramolecular H-bonds but show that the intramolecular van der Waals interaction energy is more favorable for the flexible than for the extended peptides, seemingly favoring this hypothesis. The large fluctuations in the vdw energy may make attributing the collapse of the peptide to this intramolecular energy difficult. PMID:24328358
Nanoencapsulation of Biologically Active Peptides from Whey Proteins
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Sebnem Tellioglu Harsa
Full Text Available "Now a days consumers, in order to feed with balanced diet, prefer healthy and reliable foods. In this respect food manufacturers are trying to respond the demands of consumers by developing new types of foods such as diet foods ( low calorie foods, modified foods (organic foods and functional foods (probiotic and prebiotics. Thus, production of nutritious, functional and beneficial foods has become a growing sector in the United States and European countries. Proteins are major source of many bioactive peptides. Bioactive peptides have been defined as specific protein fragments that have a positive impact on body functions and may ultimately influence human health. These peptides stay inactive within the main protein structure and activated by the enzymatic hydrolysis. These bioactive peptides, derived from proteins, are able to influence basic body systems (cardiovascular, nervous, gastrointestinal and immune systems and show multi-functional character. Due to these properties, studies have recently been focused on milk proteins and their bioactive peptides. Such peptides are inactive within the sequence of the milk protein. Whey contains a multitude of biologically active proteins and peptides. Physiologically active serum proteins are serum albumin, immunoglobulins, proteose-peptone, lactoferrin, lactoperoxidase and growth factors. In addition to these, enzymatic degradation of serum proteins releases a number of bioactive peptides such as alfa-lactophorin, beta-lactophorin, beta- lactotensin, lactokinin, albutensin, serophorin and lactoferricin. One of the common qualities of bioactive substances is their sensitivity to the physical and chemical properties of the environment. For this reason, the usefulness of bioactive components in food is limited by the structure. In order to sustain bioavailibility of these peptides, limiting its relationship with the media by encapsulation technology is one of them osthotly debated issues on in recent
Bioactive Mimetics of Conotoxins and other Venom Peptides
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Peter J. Duggan
Full Text Available Ziconotide (Prialt®, a synthetic version of the peptide ω-conotoxin MVIIA found in the venom of a fish-hunting marine cone snail Conus magnus, is one of very few drugs effective in the treatment of intractable chronic pain. However, its intrathecal mode of delivery and narrow therapeutic window cause complications for patients. This review will summarize progress in the development of small molecule, non-peptidic mimics of Conotoxins and a small number of other venom peptides. This will include a description of how some of the initially designed mimics have been modified to improve their drug-like properties.
Bioactive Mimetics of Conotoxins and other Venom Peptides
Duggan, Peter J.; Kellie L Tuck
Ziconotide (Prialt®), a synthetic version of the peptide ω-conotoxin MVIIA found in the venom of a fish-hunting marine cone snail Conus magnus, is one of very few drugs effective in the treatment of intractable chronic pain. However, its intrathecal mode of delivery and narrow therapeutic window cause complications for patients. This review will summarize progress in the development of small molecule, non-peptidic mimics of Conotoxins and a small number of other venom peptides. This will incl...
Bioactive Mimetics of Conotoxins and other Venom Peptides.
Duggan, Peter J; Tuck, Kellie L
Ziconotide (Prialt®), a synthetic version of the peptide ω-conotoxin MVIIA found in the venom of a fish-hunting marine cone snail Conus magnus, is one of very few drugs effective in the treatment of intractable chronic pain. However, its intrathecal mode of delivery and narrow therapeutic window cause complications for patients. This review will summarize progress in the development of small molecule, non-peptidic mimics of Conotoxins and a small number of other venom peptides. This will include a description of how some of the initially designed mimics have been modified to improve their drug-like properties. PMID:26501323
A simple protocol for venom peptide barcoding in scorpions
Directory of Open Access Journals (Sweden)
Stephan Schaffrath
Full Text Available Scorpion venoms contain many species-specific peptides which target ion channels in cell membranes. Without harming the scorpions, these peptides can easily be extracted and detected by MALDI-TOF mass spectrometry. So far, only few studies compared the venom of different species solely for taxonomic purposes. Here, we describe a very simple protocol for venom extraction and mass fingerprinting that was developed for peptide barcoding (venom code for species identification and facilitates reproducibility if sample preparation is performed under field conditions. This approach may serve as suitable basis for a taxonomy-oriented scorpion toxin database that interacts with MALDI-TOF mass spectra.
Ribonuclease S-peptide as a carrier in fusion proteins.
J.S. Kim; Raines, R. T.
S-peptide (residues 1-20) and S-protein (residues 21-124) are the enzymatically inactive products of the limited digestion of ribonuclease A by subtilisin. S-peptide binds S-protein with high affinity to form ribonuclease S, which has full enzymatic activity. Recombinant DNA technology was used to produce a fusion protein having three parts: carrier, spacer, and target. The two carriers used were the first 15 residues of S-peptide (S15) and a mutant S15 in which Asp 14 had been changed to Asn...
Characterization of peptide-oligonucleotide heteroconjugates by mass spectrometry.
Jensen, O N; Kulkarni, S; Aldrich, J V; Barofsky, D F
Two peptide-oligothymidylic acids, prepared by joining an 11 residue synthetic peptide containing one internal carboxyl group (Asp side chain) to amino-linker-5'pdT6 and amino-linker-5'pdT10 oligonucleotides, were analyzed by matrix-assisted laser desorption/ionization (MALDI) on a linear time-of-flight mass spectrometer and by electrospray ionization (ESI) on a triple-quadrupole system. These synthetic compounds model peptide-nucleic acid heteroconjugates encountered in antisense research an...
Hydroxyapatite-binding peptides for bone growth and inhibition
Bertozzi, Carolyn R.; Song, Jie; Lee, Seung-Wuk
Hydroxyapatite (HA)-binding peptides are selected using combinatorial phage library display. Pseudo-repetitive consensus amino acid sequences possessing periodic hydroxyl side chains in every two or three amino acid sequences are obtained. These sequences resemble the (Gly-Pro-Hyp).sub.x repeat of human type I collagen, a major component of extracellular matrices of natural bone. A consistent presence of basic amino acid residues is also observed. The peptides are synthesized by the solid-phase synthetic method and then used for template-driven HA-mineralization. Microscopy reveal that the peptides template the growth of polycrystalline HA crystals .about.40 nm in size.
Novel alpha-MSH peptide analogs for melanoma targeting
Flook, Adam Michael
Skin cancer is the one of the most diagnosed cancers in the United States with increasing incidence over the past two decades. There are three major forms of skin cancer but melanoma is the deadliest. It is estimated that 76,690 new diagnoses of melanoma and 9,480 deaths will occur in 2013. Melanoma accounts for approximately 1.6% of all cancer related deaths and is the 5 th leading diagnosed cancer in the United States. The mean survival rate of patients diagnosed with metastatic melanoma is six months, with five year survival rates of less than 5%. In this project, we describe the design and characterization of novel melanoma-targeting peptide analogs for use in diagnostic imaging of both primary and metastatic melanoma lesions. Novel alpha-MSH peptide conjugates were designed to target the melanocortin-1 receptor present and over-expressed on melanoma cells. These peptides were synthesized and their in-vitro melanocortin-1 receptor binding affinities were established in murine melanoma cells. Once binding affinities were determined, the peptides were radiolabeled with 99mTc utilizing a novel direct radiolabeling technique developed in our laboratory. The peptides were purified via reverse-phase high performance liquid chromatography and in-vivo melanoma targeting and pharmacokinetic properties were determined in B16/F1 melanoma-bearing female C57BL/6 mice. Biodistribution and SPECT/CT imaging studies were performed with the promising 99m Tc-labeled peptide conjugates. All alpha-MSH peptide conjugates tested showed low nanomolar binding affinity for the melanocortin-1 receptor. All peptides were readily radiolabeld with 99mTc with greater than 95% radiochemical purity. All 99mTc-labeled peptides displayed high specific in-vivo melanoma tumor uptake while maintaining low normal organ accumulation, and were excreted through the urinary system in a timely fashion. In addition, all tested 99mTc-labeld alpha-MSH peptides demonstrated clear visualization of in
Isolation of antimicrobial peptides and proteins from tomato
Czech Academy of Sciences Publication Activity Database
Králová, M.; Šanda, Miloslav; Macková, M.; Macek, Tomáš
Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i, 2011 - (Slaninová, J.), s. 73-76 ISBN 978-80-86241-44-9. - (Collection Symposium Series. 13). [Biologically Active Peptides /12./. Praha (CZ), 27.04.2011-29.04.2011] Grant ostatní: GA ČR(CZ) GA522/09/1693; GA ČR(CZ) GD305/09/H008 Institutional research plan: CEZ:AV0Z40550506 Keywords : tomato * antimicrobial peptides * plant peptide isolation Subject RIV: CC - Organic Chemistry
Synthetic Channel-forming Peptides and Ion Selectivity
Institute of Scientific and Technical Information of China (English)
@@ Introduction Peptides made up of alternating L- and D- amino acids can form β-helices as in gramicidin A or cyclic peptides that aggregate to form tubes[1]. In both cases the structures are hollow with all the side chains projecting outwards. Kennedy et al. [2] postulated that peptides having the (LLLD)n configuration could form helices with every fourth side chain projecting inward.It is a fact that synthetic N-formyl-( LeuSerLeuGly)6-OH, when added to a lipid bilayer, dimerizes, to form ion channels having conductances greater than that of gramicidin.