ATP synthases use energy released by the movement of protons down a transmembrane electrochemical gradient to drive the synthesis of ATP, the universal biological energy currency. Proton flow through the F0 complex which drives the rotation of a ring of c-subunits and a complex of the gamma and epsilon-subunits, causing cyclical conformational changes in the F1 complex that are required for catalysis PMID:11062562. The ATPase F1 complex gamma subunit forms the central shaft that connects the F0 rotary motor to the F1 catalytic core. The gamma subunit functions as a rotary motor inside the cylinder formed by the alpha(3)beta(3) subunits in the F1 complex PMID:16154570.