In the initial stage, to probe the relationship between their hemolytic activity and conformational / hydrophobic properties, the peptides were subjected to extensive MD simulations in water. Particular attention was paid to the conformational mobility of the peptides and the size/integrity of their surface hydrophobic pattern. In addition, to delineate the possible changes in membrane binding properties of a pair of peptides, we performed MD simulations of p1 and 7a (differ only one L/D-mutation of Arg1) in DOPC/DOPG and DOPC bilayers which mimic bacterial and mammalian cell membranes, respectively. As previously described , key parameters of protein-membrane binding, such as the membrane-bound modes and their populations, membrane insertion depth, and peptide-membrane contacts, were analyzed and compared.