Inhibition studies of ketol-acid reductoisomerases from pathogenic microorganisms

Shun Jie Wun; Lambro A Johnson; Lv You; Ross P McGeary; Thomas Brueck; Gerhard Schenk; Luke W Guddat

doi:10.1016/j.abb.2020.108516

Inhibition studies of ketol-acid reductoisomerases from pathogenic microorganisms

Arch Biochem Biophys. 2020 Oct 15:692:108516. doi: 10.1016/j.abb.2020.108516. Epub 2020 Aug 1.

Authors

Shun Jie Wun¹, Lambro A Johnson², Lv You¹, Ross P McGeary¹, Thomas Brueck³, Gerhard Schenk⁴, Luke W Guddat⁵

Affiliations

¹ School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia.
² School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD, 4072, Australia.
³ Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, University of Munich (TUM), Garching, Germany.
⁴ School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia; Sustainable Minerals Institute, The University of Queensland, St. Lucia, QLD, 4072, Australia.
⁵ School of Chemistry and Molecular Biosciences, Australian Infectious Disease Research Centre, The University of Queensland, St. Lucia, QLD, 4072, Australia. Electronic address: luke.guddat@uq.edu.au.

PMID: 32745463
DOI: 10.1016/j.abb.2020.108516

Abstract

Ketol-acid reductoisomerase (KARI), the second enzyme in the branched-chain amino acid (BCAA) biosynthesis pathway, is an emerging target for the discovery of biocides. Here, we demonstrate that cyclopropane-1,1-dicarboxylate (CPD) inhibits KARIs from the pathogens Mycobacterium tuberculosis (Mt) and Campylobacter jejuni (Cj) reversibly with K_i values of 3.03 μM and 0.59 μM, respectively. Another reversible inhibitor of both KARIs, Hoe 704, is more potent than CPD with K_i values of 300 nM and 110 nM for MtKARI and CjKARI, respectively. The most potent inhibitor tested here is N-hydroxy-N-isopropyloxamate (IpOHA). It has a K_i of ~26 nM for MtKARI, but binds rather slowly (k_on ~900 M^-1s^-1). In contrast, IpOHA binds more rapidly (k_on ~7000 M^-1s^-1) to CjKARI and irreversibly.

Keywords: Antimicrobial chemotherapeutics; Branched-chain amino acid biosynthesis; Campylobacter jejuni; Ketol-acid reductoisomerase; Mycobacterium tuberculosis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacterial Proteins / antagonists & inhibitors*
Bacterial Proteins / chemistry
Bacterial Proteins / metabolism
Campylobacter jejuni / chemistry
Campylobacter jejuni / enzymology*
Cyclopropanes / chemistry
Dicarboxylic Acids / chemistry
Enzyme Inhibitors / chemistry*
Hydroxamic Acids / chemistry
Ketol-Acid Reductoisomerase / antagonists & inhibitors*
Ketol-Acid Reductoisomerase / chemistry
Ketol-Acid Reductoisomerase / metabolism
Mycobacterium tuberculosis / chemistry
Mycobacterium tuberculosis / enzymology*
Organophosphorus Compounds / chemistry

Substances

Bacterial Proteins
Cyclopropanes
Dicarboxylic Acids
Enzyme Inhibitors
Hydroxamic Acids
Organophosphorus Compounds
cyclopropane-1,1-dicarboxylic acid
N-hydroxy-N-isopropyloxamate
2-methylphosphinoyl-2-hydroxyacetic acid
Ketol-Acid Reductoisomerase