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Novel insight into the reaction of nitro, nitroso and hydroxylamino benzothiazinones and of benzoxacinones with Mycobacterium tuberculosis DprE1

DOI: 10.1038/s41598-018-31316-6 DOI Help

Authors: Adrian Richter (Martin-Luther-Universität Halle-Wittenberg) , Ines Rudolph (Martin-Luther-Universität Halle-Wittenberg) , Ute Möllmann (Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie - Hans-Knöll-Institut) , Kerstin Voigt (Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie - Hans-Knöll-Institut) , Chun-wa Chung (GlaxoSmithKline) , Onkar M. P. Singh (GlaxoSmithKline) , Michael Rees (GlaxoSmithKline) , Alfonso Mendoza-losana (GlaxoSmithKline) , Robert Bates (GlaxoSmithKline) , Lluís Ballell (GlaxoSmithKline) , Sarah Batt (University of Birmingham) , Natacha Veerapen (University of Birmingham) , Klaus Fütterer (University of Birmingham) , Gurdyal Besra (University of Birmingham) , Peter Imming (Martin-Luther-Universität Halle-Wittenberg) , Argyrides Argyrou (GlaxoSmithKline)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Scientific Reports , VOL 8

State: Published (Approved)
Published: September 2018
Diamond Proposal Number(s): 12279

Open Access Open Access

Abstract: Nitro-substituted 1,3-benzothiazinones (nitro-BTZs) are mechanism-based covalent inhibitors of Mycobacterium tuberculosis decaprenylphosphoryl-β-D-ribose-2′-oxidase (DprE1) with strong antimycobacterial properties. We prepared a number of oxidized and reduced forms of nitro-BTZs to probe the mechanism of inactivation of the enzyme and to identify opportunities for further chemistry. The kinetics of inactivation of DprE1 was examined using an enzymatic assay that monitored reaction progress up to 100 min, permitting compound ranking according to kinact/Ki values. The side-chain at the 2-position and heteroatom identity at the 1-position of the BTZs were found to be important for inhibitory activity. We obtained crystal structures with several compounds covalently bound. The data suggest that steps upstream from the covalent end-points are likely the key determinants of potency and reactivity. The results of protein mass spectrometry using a 7-chloro-nitro-BTZ suggest that nucleophilic reactions at the 7-position do not operate and support a previously proposed mechanism in which BTZ activation by a reduced flavin intermediate is required. Unexpectedly, a hydroxylamino-BTZ showed time-dependent inhibition and mass spectrometry corroborated that this hydroxylamino-BTZ is a mechanism-based suicide inhibitor of DprE1. With this BTZ derivative, we propose a new covalent mechanism of inhibition of DprE1 that takes advantage of the oxidation cycle of the enzyme.

Journal Keywords: Drug discovery and development; Molecular medicine

Subject Areas: Biology and Bio-materials

Instruments: I03-Macromolecular Crystallography

Other Facilities: ESRF