InterPro domain: IPR014031

Beta-ketoacyl-ACP synthase 2.3.1.41 (KAS) [ 1 ] is the enzyme that catalyses the condensation of malonyl-ACP with the growing fatty acid chain. It is found as a component of a number of enzymatic systems, including fatty acid synthetase (FAS), which catalyses theformation of long-chain fatty acids from acetyl-CoA, malonyl-CoA and NADPH; the multi-functional 6-methysalicylic acid synthase (MSAS) from Penicillium patulum [ 2 ], which is involved in the biosynthesis of a polyketide antibiotic; polyketide antibiotic synthase enzymesystems; Emericella nidulans multifunctional protein Wa, which is involved in the biosynthesis of conidial green pigment; Rhizobium nodulation protein nodE, which probably acts as a beta-ketoacyl synthase in the synthesis of the nodulation Nod factor fatty acyl chain; and yeast mitochondrial protein CEM1. The condensation reaction is a two step process, first the acyl component of an activated acyl primer is transferred to a cysteine residue of the enzyme and is then condensed with an activated malonyl donor with the concomitant release of carbon dioxide.

This entry represents the C-terminal domain of beta-ketoacyl-ACP synthases. The active site is contained in a cleft between N- and C-terminal domains, with residues from both domains contributing to substrate binding and catalysis [ 3 ].

1. beta-Ketoacyl-ACP synthase I of Escherichia coli: nucleotide sequence of the fabB gene and identification of the cerulenin binding residue. Carlsberg Res. Commun. 53, 357-70
2. The multifunctional 6-methylsalicylic acid synthase gene of Penicillium patulum. Its gene structure relative to that of other polyketide synthases. Eur. J. Biochem. 192, 487-98
3. The crystal structure of beta-ketoacyl-acyl carrier protein synthase II from Synechocystis sp. at 1.54 A resolution and its relationship to other condensing enzymes. J. Mol. Biol. 305, 491-503