4RL1

Structural and functional analysis of a loading acyltransferase from the avermectin modular polyketide synthase

Summary for 4RL1

• Entry DOI: 10.2210/pdb4rl1/pdb
• Descriptor: Type I polyketide synthase AVES 1 (2 entities in total)
• Functional Keywords: hydrolase, ferredoxin-like fold, acyltransferase, transferase
• Biological source: Streptomyces avermitilis
• Total number of polymer chains: 1
• Total formula weight: 39753.89

Authors

Wang, F.,Wang, Y.,Zheng, J. (deposition date: 2014-10-15, release date: 2015-01-28, Last modification date: 2023-09-20)

Primary citation

Wang, F.,Wang, Y.,Ji, J.,Zhou, Z.,Yu, J.,Zhu, H.,Su, Z.,Zhang, L.,Zheng, J.
Structural and functional analysis of the loading acyltransferase from avermectin modular polyketide synthase.
Acs Chem.Biol., 10:1017-1025, 2015

PubMed Abstract: The loading acyltransferase (AT) domains of modular polyketide synthases (PKSs) control the choice of starter units incorporated into polyketides and are therefore attractive targets for the engineering of modular PKSs. Here, we report the structural and biochemical characterizations of the loading AT from avermectin modular PKS, which accepts more than 40 carboxylic acids as alternative starter units for the biosynthesis of a series of congeners. This first structural analysis of loading ATs from modular PKSs revealed the molecular basis for the relaxed substrate specificity. Residues important for substrate binding and discrimination were predicted by modeling a substrate into the active site. A mutant with altered specificity toward a panel of synthetic substrate mimics was generated by site-directed mutagenesis of the active site residues. The hydrolysis of the N-acetylcysteamine thioesters of racemic 2-methylbutyric acid confirmed the stereospecificity of the avermectin loading AT for an S configuration at the C-2 position of the substrate. Together, these results set the stage for region-specific modification of polyketides through active site engineering of loading AT domains of modular PKSs.

PubMed: 25581064
DOI: 10.1021/cb500873k

Experimental method

X-RAY DIFFRACTION (2 Å)