Insights into the Physiology and Metabolism of a Mycobacterial Cell in an Energy-Compromised State.

, a bacterium that causes tuberculosis, poses a serious threat, especially due to the emergence of drug-resistant strains. and other mycobacterial species, such as , are known to generate an inadequate amount of energy by substrate-level phosphorylation and mandatorily require oxidative phosphorylation (OXPHOS) for their growth and metabolism. Hence, antibacterial drugs, such as bedaquiline, targeting the multisubunit ATP synthase complex, which is required for OXPHOS, have been developed with the aim of eliminating pathogenic mycobacteria. Here, we explored the influence of suboptimal OXPHOS on the physiology and metabolism of harbors two identical copies of , which codes for the β subunit of ATP synthase. We show that upon deletion of one copy of ( Δ), synthesizes smaller amounts of ATP and enters into an energy-compromised state. The mutant displays remarkable phenotypic and physiological differences from the wild type, such as respiratory slowdown, reduced biofilm formation, lesser amounts of cell envelope polar lipids, and increased antibiotic sensitivity compared to the wild type. Additionally, Δ overexpresses genes belonging to the dormancy operon, the β-oxidation pathway, and the glyoxylate shunt, suggesting that the mutant adapts to a low energy state by switching to alternative pathways to produce energy. Interestingly, Δ shows significant phenotypic, metabolic, and physiological similarities with bedaquiline-treated wild-type We believe that the identification and characterization of key metabolic pathways functioning during an energy-compromised state will enhance our understanding of bacterial adaptation and survival and will open newer avenues in the form of drug targets that may be used in the treatment of mycobacterial infections. generates an inadequate amount of energy by substrate-level phosphorylation and mandatorily requires oxidative phosphorylation (OXPHOS) for its growth and metabolism. Here, we explored the influence of suboptimal OXPHOS on physiology and metabolism. harbors two identical copies of the gene, which codes for the ATP synthase β subunit. Here, we carried out the deletion of only one copy of in to understand the bacterial survival response in an energy-deprived state. Δ shows remarkable phenotypic, metabolic, and physiological differences from the wild type. Our study thus establishes Δ as an energy-compromised mycobacterial strain, highlights the importance of ATP synthase in mycobacterial physiology, and further paves the way for the identification of novel antimycobacterial drug targets.