Discovery of a Novel Mycobacterial F‐ATP Synthase Inhibitor and its Potency in Combination with Diarylquinolines

The F1 FO -ATP synthase is required for growth and viability of Mycobacterium tuberculosis and is a validated clinical target. A mycobacterium-specific loop of the enzyme's rotary γ subunit plays a role in the coupling of ATP synthesis within the enzyme complex. We report the discovery of a novel antimycobacterial, termed GaMF1, that targets this γ subunit loop. Biochemical and NMR studies show that GaMF1 inhibits ATP synthase activity by binding to the loop. GaMF1 is bactericidal and is active against multidrug- as well as bedaquiline-resistant strains. Chemistry efforts on the scaffold revealed a dynamic structure activity relationship and delivered analogues with nanomolar potencies. Combining GaMF1 with bedaquiline or novel diarylquinoline analogues showed potentiation without inducing genotoxicity or phenotypic changes in a human embryonic stem cell reporter assay. These results suggest that GaMF1 presents an attractive lead for the discovery of a novel class of anti-tuberculosis F-ATP synthase inhibitors. National Research Foundation (NRF) Accepted version This research was supported by the National ResearchFoundation (NRF) Singapore,NRF Competitive Research Programme (CRP), Grant Award Number NRF-CRP18-2017-01. A. Hotra is grateful to receive an IGS PremiumScholarship,Institute of Technology in Health and Medicineat NTU,and J. P. Sarathy received aPhD scholarship from theSchool of Medicine,NUS,Singapore.Wethank Dr. YongxinLi for the X-ray crystallographic structure determinations.