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A dual transacylation mechanism for polyketide synthase chain release in enacyloxin antibiotic biosynthesis.

Accepted version
Peer-reviewed

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Authors

Masschelein, Joleen  ORCID logo  https://orcid.org/0000-0003-4366-3675
Sydor, Paulina K 
Hobson, Christian 
Howe, Rhiannon 

Abstract

Polyketide synthases assemble diverse natural products with numerous important applications. The thioester intermediates in polyketide assembly are covalently tethered to acyl carrier protein domains of the synthase. Several mechanisms for polyketide chain release are known, contributing to natural product structural diversification. Here, we report a dual transacylation mechanism for chain release from the enacyloxin polyketide synthase, which assembles an antibiotic with promising activity against Acinetobacter baumannii. A non-elongating ketosynthase domain transfers the polyketide chain from the final acyl carrier protein domain of the synthase to a separate carrier protein, and a non-ribosomal peptide synthetase condensation domain condenses it with (1S,3R,4S)-3,4-dihydroxycyclohexane carboxylic acid. Molecular dissection of this process reveals that non-elongating ketosynthase domain-mediated transacylation circumvents the inability of the condensation domain to recognize the acyl carrier protein domain. Several 3,4-dihydroxycyclohexane carboxylic acid analogues can be employed for chain release, suggesting a promising strategy for producing enacyloxin analogues.

Description

Keywords

Acinetobacter baumannii, Acylation, Anti-Bacterial Agents, Microbial Sensitivity Tests, Molecular Structure, Polyenes, Polyketide Synthases

Journal Title

Nat Chem

Conference Name

Journal ISSN

1755-4330
1755-4349

Volume Title

11

Publisher

Springer Science and Business Media LLC

Rights

All rights reserved
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/L021692/1)