The alpha/beta subunits undergo a sequence of conformational changes leading to the formation of ATP from ADP, which are induced by the rotation of the gamma subunit, itself is driven by the movement of protons through the Fo complex C subunit. In V- and A-ATPases, the alpha/A and beta/B subunits of the V1 or A1 complex are homologous to the alpha and beta subunits in the F1 complex of F-ATPases, except that the alpha subunit is catalytic and the beta subunit is regulatory. The alpha/A and beta/B subunits can each be divided into three regions, or domains, centred on the ATP-binding pocket, and based on structure and function. The central domain contains the nucleotide-binding residues that make direct contact with the ADP/ATP molecule. Human proteins containing this domain ATP5A1; ATP5B; ATP6V1A; ATP6V1B1; ATP6V1B2; References Protein domains Protein families Transmembrane proteins