Mitochondrial ATP synthase (Complex V) synthesizes ATP from ADP and inorganic phosphate using the energy provided by the proton electrochemical gradient across the inner mitochondrial membrane. It consists of two structural domains: the F[[1]] sector, a soluble portion situated in the mitochondrial matrix, and the F[[0]] sector, which spans the inner mitochondrial membrane. The F[[1]] sector is composed of three copies each of subunits alpha and beta, which form the catalytic core that synthesizes ATP, and one each of subunits gamma, delta and epsilon, which constitute the central stalk. (Adapted from PMID:21874297.)