Enzymes
| UniProtKB help_outline | 4 proteins |
Reaction participants Show >> << Hide
- Name help_outline octanoyl-CoA Identifier CHEBI:57386 Charge -4 Formula C29H46N7O17P3S InChIKeyhelp_outline KQMZYOXOBSXMII-CECATXLMSA-J SMILEShelp_outline CCCCCCCC(=O)SCCNC(=O)CCNC(=O)[C@H](O)C(C)(C)COP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1OP([O-])([O-])=O)n1cnc2c(N)ncnc12 2D coordinates Mol file for the small molecule Search links Involved in 31 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
malonyl-[ACP]
Identifier
RHEA-COMP:9623
Reactive part
help_outline
- Name help_outline O-(S-malonylpantetheine-4ʼ-phosphoryl)-L-serine residue Identifier CHEBI:78449 Charge -2 Formula C17H26N3O11PS SMILEShelp_outline CC(C)(COP([O-])(=O)OC[C@H](N-*)C(-*)=O)[C@@H](O)C(=O)NCCC(=O)NCCSC(=O)CC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 37 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,521 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
3-oxodecanoyl-[ACP]
Identifier
RHEA-COMP:9637
Reactive part
help_outline
- Name help_outline O-(S-3-oxodecanoylpantetheine-4ʼ-phosphoryl)-L-serine residue Identifier CHEBI:78464 Charge -1 Formula C24H41N3O10PS SMILEShelp_outline CCCCCCCC(=O)CC(=O)SCCNC(=O)CCNC(=O)[C@H](O)C(C)(C)COP([O-])(=O)OC[C@H](N-*)C(-*)=O 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CO2 Identifier CHEBI:16526 (CAS: 124-38-9) help_outline Charge 0 Formula CO2 InChIKeyhelp_outline CURLTUGMZLYLDI-UHFFFAOYSA-N SMILEShelp_outline O=C=O 2D coordinates Mol file for the small molecule Search links Involved in 1,006 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CoA Identifier CHEBI:57287 (Beilstein: 11604429) help_outline Charge -4 Formula C21H32N7O16P3S InChIKeyhelp_outline RGJOEKWQDUBAIZ-IBOSZNHHSA-J SMILEShelp_outline CC(C)(COP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1OP([O-])([O-])=O)n1cnc2c(N)ncnc12)[C@@H](O)C(=O)NCCC(=O)NCCS 2D coordinates Mol file for the small molecule Search links Involved in 1,511 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:42264 | RHEA:42265 | RHEA:42266 | RHEA:42267 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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| MetaCyc help_outline |
Publications
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Beta-ketoacyl-acyl carrier protein synthase III (FabH) is a determining factor in branched-chain fatty acid biosynthesis.
Choi K.-H., Heath R.J., Rock C.O.
A universal set of genes encodes the components of the dissociated, type II, fatty acid synthase system that is responsible for producing the multitude of fatty acid structures found in bacterial membranes. We examined the biochemical basis for the production of branched-chain fatty acids by gram- ... >> More
A universal set of genes encodes the components of the dissociated, type II, fatty acid synthase system that is responsible for producing the multitude of fatty acid structures found in bacterial membranes. We examined the biochemical basis for the production of branched-chain fatty acids by gram-positive bacteria. Two genes that were predicted to encode homologs of the beta-ketoacyl-acyl carrier protein synthase III of Escherichia coli (eFabH) were identified in the Bacillus subtilis genome. Their protein products were expressed, purified, and biochemically characterized. Both B. subtilis FabH homologs, bFabH1 and bFabH2, carried out the initial condensation reaction of fatty acid biosynthesis with acetyl-coenzyme A (acetyl-CoA) as a primer, although they possessed lower specific activities than eFabH. bFabH1 and bFabH2 also utilized iso- and anteiso-branched-chain acyl-CoA primers as substrates. eFabH was not able to accept these CoA thioesters. Reconstitution of a complete round of fatty acid synthesis in vitro with purified E. coli proteins showed that eFabH was the only E. coli enzyme incapable of using branched-chain substrates. Expression of either bFabH1 or bFabH2 in E. coli resulted in the appearance of a branched-chain 17-carbon fatty acid. Thus, the substrate specificity of FabH is an important determinant of branched-chain fatty acid production. << Less
J. Bacteriol. 182:365-370(2000) [PubMed] [EuropePMC]
This publication is cited by 22 other entries.
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Identification and substrate specificity of beta -ketoacyl (acyl carrier protein) synthase III (mtFabH) from Mycobacterium tuberculosis.
Choi K.-H., Kremer L., Besra G.S., Rock C.O.
The long-chain alpha-alkyl-beta-hydroxy fatty acids, termed mycolic acids, which are characteristic components of the mycobacterial cell wall are produced by successive rounds of elongation catalyzed by a multifunctional (type I) fatty acid synthase complex followed by a dissociated (type II) fatt ... >> More
The long-chain alpha-alkyl-beta-hydroxy fatty acids, termed mycolic acids, which are characteristic components of the mycobacterial cell wall are produced by successive rounds of elongation catalyzed by a multifunctional (type I) fatty acid synthase complex followed by a dissociated (type II) fatty acid synthase. In bacterial type II systems, the first initiation step in elongation is the condensation of acetyl-CoA with malonyl-acyl carrier protein (ACP) catalyzed by beta-ketoacyl-ACP III (FabH). An open reading frame in the Mycobacterium tuberculosis genome (Rv0533c), now termed mtfabH, was 37.3% identical to Escherichia coli ecFabH and contained the Cys-His-Asn catalytic triad signature. However, the purified recombinant mtFabH clearly preferred long-chain acyl-CoA substrates rather than acyl-ACP primers and did not utilize acetyl-CoA as a primer in comparison to ecFabH. In addition, purified mtFabH was sensitive to thiolactomycin and resistant to cerulenin in an in vitro assay. However, mtFabH overexpression in Mycobacterium bovis BCG did not confer thiolactomycin resistance, suggesting that mtFabH may not be the primary target of thiolactomycin inhibition in vivo and led to several changes in the lipid composition of the bacilli. The data presented is consistent with a role for mtFabH as the pivotal link between the type I and type II fatty acid elongation systems in M. tuberculosis. This study opens up new avenues for the development of selective and novel anti-mycobacterial agents targeted against mtFabH. << Less
J. Biol. Chem. 275:28201-28207(2000) [PubMed] [EuropePMC]
This publication is cited by 5 other entries.
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Crystal structure of the Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III.
Scarsdale J.N., Kazanina G., He X., Reynolds K.A., Wright H.T.
Mycolic acids (alpha-alkyl-beta-hydroxy long chain fatty acids) cover the surface of mycobacteria, and inhibition of their biosynthesis is an established mechanism of action for several key front-line anti-tuberculosis drugs. In mycobacteria, long chain acyl-CoA products (C(14)-C(26)) generated by ... >> More
Mycolic acids (alpha-alkyl-beta-hydroxy long chain fatty acids) cover the surface of mycobacteria, and inhibition of their biosynthesis is an established mechanism of action for several key front-line anti-tuberculosis drugs. In mycobacteria, long chain acyl-CoA products (C(14)-C(26)) generated by a type I fatty-acid synthase can be used directly for the alpha-branch of mycolic acid or can be extended by a type II fatty-acid synthase to make the meromycolic acid (C(50)-C(56)))-derived component. An unusual Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein (ACP) synthase III (mtFabH) has been identified, purified, and shown to catalyze a Claisen-type condensation between long chain acyl-CoA substrates such as myristoyl-CoA (C(14)) and malonyl-ACP. This enzyme, presumed to play a key role in initiating meromycolic acid biosynthesis, was crystallized, and its structure was determined at 2.1-A resolution. The mtFabH homodimer is closely similar in topology and active-site structure to Escherichia coli FabH (ecFabH), with a CoA/malonyl-ACP-binding channel leading from the enzyme surface to the buried active-site cysteine residue. Unlike ecFabH, mtFabH contains a second hydrophobic channel leading from the active site. In the ecFabH structure, this channel is blocked by a phenylalanine residue, which constrains specificity to acetyl-CoA, whereas in mtFabH, this residue is a threonine, which permits binding of longer acyl chains. This same channel in mtFabH is capped by an alpha-helix formed adjacent to a 4-amino acid sequence insertion, which limits bound acyl chain length to 16 carbons. These observations offer a molecular basis for understanding the unusual substrate specificity of mtFabH and its probable role in regulating the biosynthesis of the two different length acyl chains required for generation of mycolic acids. This mtFabH presents a new target for structure-based design of novel antimycobacterial agents. << Less
J. Biol. Chem. 276:20516-20522(2001) [PubMed] [EuropePMC]
This publication is cited by 4 other entries.