within a GHSLG pentapeptide. FabD first binds malonyl-CoA, the malonyl moiety is then transferred to the active siteSer 92, and CoA is released from the enzyme. ACP then binds and the malonyl moiety is transferred to the terminal sulfhydryl of the ACP prosthetic group. This reaction is readily reversible. Industrial relevance Among all known metabolic pathways in living systems, fatty acid biosynthesis yields the most energy dense products. As a result, microbial fatty acid derivatives are emerging as a promising renewable energy alternative to fossil fuel derived transportation fuels. Recently, Khosla et al. have devised a procedure to reconstitute E.Coli Fatty Acid Synthase using purified protein components (including FabD) and reported a detailed kinetic analysis of this in-vitro reconstituted system. Their finding provide a new basis for assessing the scope and limitations of using E.Coli as a biocatalyst for the production of diesel fuels. Clinical relevance FabD as a target for Antibacterial Drug Discovery: An upcoming field Fatty acid biosynthesis is carried out by the ubiquitous Fatty Acid Synthase. Fatty acid synthase pathways are divided into two distinct molecular forms: Type I and Type II. In Type I, Fatty Acid Synthase (found in humans and other mammals) is a single large polypeptide composed of several distinct domains. On the other hand, each enzymatic activity (Condensation reaction, Reduction Reaction, Dehydration reaction) is found as a discrete protein in type II systems. The difference in active site organization and predominance of type II FAS systems in bacteria make the enzymes of this pathway attractive targets for antibacterials. FabD (Acyl-Carrier-Protein S-Malonyltransferase) is a reasonable target given that a high resolution crystal structure is available. However, no FabD inhibitors have been reported in the literature and review articles on this topic. The simple structure and acidity of malonate seem to permit few approaches to synthesizing derivatives (acting as potential inhibitors) that retain the character of the molecule. A second approach for using FabD as a drug target is frequently identified in the literature: FabD can provide a useful tag for locating fab genes because FabD gene is usually adjacent to at least one other fab gene. However (as of 2015), no potential drugs have attempted to exploit this feature. References Further reading EC 2.3.1 Enzymes of known structure Articles containing video clips