Mycobacterium tuberculosis relies on host-derived lipids, including cholesterol, for intracellular survival, generating propionyl-CoA-a metabolite that must be efficiently assimilated to prevent toxicity. The metallophosphoesterase Rv0805 is required for optimal growth on cholesterol, and an Rv0805 knockout strain exhibits impaired ability to colonize the murine lung. However, the mechanisms underlying the essential role of Rv0805 under host-relevant conditions remain unclear. The deletion of the rv0805 ortholog (bcg₀857) in Mycobacterium bovis BCG reveals that both its catalytic activity and membrane localization are essential for growth on propionate, a by-product of cholesterol metabolism. Loss of Rv0805 impaired propionate uptake, altered cell envelope lipid composition with an accumulation of methyl-branched lipids, and reduced carbon flux through the methylcitrate cycle, ultimately depleting key central carbon metabolites required for growth. Vitamin B12 supplementation activated the methylmalonyl pathway, restoring metabolic balance and rescuing growth. These findings demonstrate that Rv0805 links propionate metabolism with cell envelope integrity, identifying its activity and localization as metabolic vulnerabilities that could be exploited for tuberculosis therapy. IMPORTANCERv0805 links propionate metabolism with cell envelope homeostasis in mycobacteria, and its loss uncovers a metabolic vulnerability that could be exploited to restrict mycobacterial survival in lipid-rich host microenvironments.
Biswas et al. (Fri,) studied this question.