The Unique C-Terminal Extension of Mycobacterial F-ATP Synthase Subunit α Is the Major Contributor to Its Latent ATP Hydrolysis Activity

Mycobacterial F₁F_o-ATP synthases (α₃:β₃:γ:δ:ε:a:b:b=:c₉) are incapable of ATP-driven proton translocation due to their latent ATPase activity. This prevents wasting of ATP and altering of the proton motive force, whose dissipation is lethal to mycobacteria. We demonstrate that the mycobacterial C-terminal extension of nucleotide-binding subunit α contributes mainly to the suppression of ATPase activity in the recombinant mycobacterial F₁-ATPase. Using C-terminal deletion mutants, the regions responsible for the enzyme’s latency were mapped, providing a new compound epitope.