CATH Classification

Domain Context

CATH Clusters

Superfamily 3.40.47.10
Functional Family

Enzyme Information

2.3.1.180
Beta-ketoacyl-[acyl-carrier-protein] synthase III.
based on mapping to UniProt Q820T1
Acetyl-CoA + malonyl-[acyl-carrier-protein] = acetoacetyl-[acyl-carrier- protein] + CoA + CO(2).
-!- Involved in the dissociated (or type II) fatty-acid biosynthesis system that occurs in plants and bacteria. -!- In contrast to EC 2.3.1.41 and EC 2.3.1.179, this enzyme specifically uses CoA thioesters rather than acyl-ACP as the primer. -!- In addition to the above reaction, the enzyme can also catalyze the reaction of EC 2.3.1.38, but to a much lesser extent. -!- Responsible for initiating both straight- and branched-chain fatty- acid biosynthesis, with the substrate specificity in an organism reflecting the fatty-acid composition found in that organism. -!- For example, Streptococcus pneumoniae, a Gram-positive bacterium, is able to use both straight- and branched-chain (C4--C6) acyl-CoA primers whereas Escherichia coli, a Gram-negative organism, uses primarily short straight-chain acyl CoAs, with a preference for acetyl-CoA.

UniProtKB Entries (1)

Q820T1
FABH_ENTFA
Enterococcus faecalis V583
3-oxoacyl-[acyl-carrier-protein] synthase 3

PDB Structure

PDB 3IL4
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Crystal structures of bacterial FabH suggest a molecular basis for the substrate specificity of the enzyme.
Gajiwala, K.S., Margosiak, S., Lu, J., Cortez, J., Su, Y., Nie, Z., Appelt, K.
Febs Lett.