Structural enzymology of spirotetronate cyclases

Abstract

The accelerating emergence of antimicrobial resistance is an increasingly significant problem that threatens human health and economic development on a global scale. As a consequence, the identification of hitherto unexploited drug targets, and the generation of new effective antibiotics, are considered urgent and strategically important endeavours. Amongst natural product-based antibiotics, the polyketide-derived spirotetronates constitute an attractive family of clinical candidates due to their potent bioactivities and suitability for chemical derivatisation. During spirotetronate biosynthesis, Diels-Alder reactions are performed by dedicated [4+2] cyclases to generate the characteristic spirocyclic core common to these natural products. The [4+2] cyclases from the chlorothricin and tetronasin biosynthetic pathways have to date remained largely unstudied, despite their essential role in the biosynthesis of these antimicrobial compounds. The studies outlined herein have sought to address this knowledge gap, by adopting a two-pronged experimental approach, coupling in vitro structural and functional analyses of these enzymes with in vivo gene knock-out studies in authentic producer strains. In undertaking these studies, important new insights have been gleaned into the mechanistic enzymology of spirotetronate biosynthesis. In related investigations, the enzyme pyruvate kinase (Pyk) from methicillin-resistant Staphylococcus aureus (MRSA) has been investigated as a potential target for antibiotic intervention and drug development. Chemical derivatisation, along with structural, functional and microbial studies have been used to investigate the potential of natural product-inspired bisindole compounds for use as clinical agents targeting MRSA Pyk.

Date of Award	4 Feb 2025
Original language	English
Awarding Institution	University of Bristol
Supervisor	Paul R Race (Supervisor) & Chris L Willis (Supervisor)