Structural and Biochemical insights to the Recruitment of Acyl Carrier Protein-linked Extender Units in Ansamitocin Biosynthesis.

Structural and Biochemical insights to the Recruitment of Acyl Carrier Protein-linked Extender Units in Ansamitocin Biosynthesis.
Chembiochem. 2019 Nov 27;:
Authors: Zhang F, Ji H, Ali I, Deng Z, Bai L, Zheng J
Abstract
A few acyltransferase (AT) domains of modular polyketide synthases (PKSs) recruit acyl carrier protein (ACP)-linked extender units with unusual C2 substituents to confer functionalities that are not available in coenzyme A (CoA)-linked ones. Here, an AT specific for methoxymalonyl (MOM)-ACP in the third module of the ansamitocin PKS was structurally and biochemically characterized. The AT uses a conserved tryptophan at the entrance of the substrate binding tunnel to discriminate between different carriers. A W275R mutation switches its carrier specificity from the ACP protein to the CoA molecule. The acyl-AT complex structures clearly show that the MOM-ACP accepted by the AT has the 2S instead of the opposite 2R stereochemistry that is predicted according to the biosynthetic derivation from a D-glycolytic intermediate. Together, these results reveal the structural basis of ATs recognizing ACP-linked extender units in polyketide biosynthesis.
PMID: 31777147 [PubMed - as supplied by publisher]

Source: Chembiochem - November 26, 2019 Category: Biochemistry Authors: Zhang F, Ji H, Ali I, Deng Z, Bai L, Zheng J Tags: Chembiochem Source Type: research