Structure and Function of the  α-Hydroxylation Bimodule of the Mupirocin Polyketide Synthase

Angew Chem Int Ed Engl. 2023 Sep 28:e202312514. doi: 10.1002/anie.202312514. Online ahead of print.ABSTRACTMupirocin is a clinically important antibiotic produced by a trans-AT Type I polyketide synthase (PKS) in Pseudomonas fluorescens. The major bioactive metabolite, pseudomonic acid A (PA-A), is assembled on a tetrasubstituted tetrahydropyran (THP) core incorporating a 6-hydroxyl group proposed to be introduced via α-hydroxylation of the thioester of the acyl carrier protein (ACP) bound polyketide chain. Herein, we describe an in vitro approach combining purified enzyme components, chemical synthesis, isotopic labelling, mass spectrometry and NMR in conjunction with in vivo studies leading to the first characterisation of the α-hydroxylation bimodule of the mupirocin biosynthetic pathway. These studies reveal the precise timing of hydroxylation by MupA, substrate specificity and the ACP dependency of the enzyme components that comprise this α-hydroxylation bimodule. Furthermore, using purified enzyme, it is shown that the MmpA KS0 shows relaxed substrate specificity, suggesting precise spatio-temporal control of in-trans MupA recruitment versus inter-module (MmpD to MmpA) transfer. Finally, detection of multiple intermodular-modular MupA/ACP interactions suggest these bimodules may integrate MupA into their assembly.PMID:37768840 | DOI:10.1002/anie.202312514

Source: Angewandte Chemie - September 28, 2023 Category: Chemistry Authors: Ashley J Winter Nisha Khanizeman Abigail M C Barker-Mountford Andrew James Devine Luoyi Wang Zhongshu Song Jonathan A Davies Paul R Race Christopher Williams Thomas James Simpson Christine L Willis Matthew Philip Crump Source Type: research