4hxy

Publication Abstract from PubMed

The formation of an activated cis-3-cyclohexylpropenoic acid by Plm1, the first extension module of the phoslactomycin polyketide synthase, is proposed to occur through an L-3-hydroxyacyl-intermediate as a result of ketoreduction by an A-type ketoreductase (KR). Here, we demonstrate that the KR domain of Plm1 (PlmKR1) catalyzes the formation of an L-3-hydroxyacyl product. The crystal structure of PlmKR1 revealed a well-ordered active site with a nearby Trp residue characteristic of A-type KRs. Structural comparison of PlmKR1 with B-type KRs that produce D-3-hydroxyacyl intermediates revealed significant differences. The active site of cofactor-bound A-type KRs is in a catalysis-ready state, whereas cofactor-bound B-type KRs are in a precatalytic state. Furthermore, the closed lid loop in substrate-bound A-type KRs restricts active site access from all but one direction, which is proposed to control the stereochemistry of ketoreduction.

Structural and Stereochemical Analysis of a Modular Polyketide Synthase Ketoreductase Domain Required for the Generation of a cis-Alkene.,Bonnett SA, Whicher JR, Papireddy K, Florova G, Smith JL, Reynolds KA Chem Biol. 2013 Jun 20;20(6):772-83. doi: 10.1016/j.chembiol.2013.04.014. PMID:23790488^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.