2qx1
From Proteopedia
Crystal structure of the complex between mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III (FABH) and decyl-COA disulfide
Structural highlights
FunctionFABH_MYCTU Catalyzes the condensation reaction of fatty acid synthesis by the addition to an acyl acceptor of two carbons from malonyl-ACP. Catalyzes the first condensation reaction which initiates fatty acid synthesis and may therefore play a role in governing the total rate of fatty acid production. Possesses both acetoacetyl-ACP synthase and acetyl transacylase activities. Has some substrate specificity for long chain acyl-CoA such as myristoyl-CoA. Does not use acyl-CoA as primer. Its substrate specificity determines the biosynthesis of mycolic acid fatty acid chain, which is characteristic of mycobacterial cell wall.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe dimeric Mycobacterium tuberculosis FabH (mtFabH) catalyses a Claisen-type condensation between an acyl-CoA and malonyl-acyl carrier protein (ACP) to initiate the Type II fatty acid synthase cycle. To analyze the initial covalent acylation of mtFabH with acyl-CoA, we challenged it with mixture of C6-C20 acyl-CoAs and the ESI-MS analysis showed reaction at both subunits and a strict specificity for C12 acyl CoA. Crystallographic and ESI-MS studies of mtFabH with a decyl-CoA disulfide inhibitor revealed a decyl chain bound in acyl-binding channels of both subunits through disulfide linkage to the active site cysteine. These data provide the first unequivocal evidence that both subunits of mtFabH can react with substrates or inhibitor. The discrepancy between the observed C12 acyl-CoA substrate specificity in the initial acylation step and the higher catalytic efficiency of mtFabH for C18-C20 acyl-CoA substrates in the overall mtFabH catalyzed reaction suggests a role for M. tuberculosis ACP as a specificity determinant in this reaction. Probing reactivity and substrate specificity of both subunits of the dimeric Mycobacterium tuberculosis FabH using alkyl-CoA disulfide inhibitors and acyl-CoA substrates.,Sachdeva S, Musayev F, Alhamadsheh MM, Neel Scarsdale J, Tonie Wright H, Reynolds KA Bioorg Chem. 2008 Apr;36(2):85-90. Epub 2007 Dec 21. PMID:18096200[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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