Produces ATP from ADP in the presence of a proton gradient across the membrane. The gamma chain is believed to be important in regulating ATPase activity and the flow of protons through the CF(0) complex. F-type ATPases have 2 components, CF(1) - the catalytic core - and CF(0) - the membrane proton channel. CF(1) has five subunits: alpha(3), beta(3), gamma(1), delta(1), epsilon(1). CF(0) has four main subunits: a, b, b' and c (By similarity). Disulfide bond; Cys-240 and Cys-246 are known to form a disulfide bridge in the dark which gives rise to an inactive enzyme. Activation can be brought about by a ferredoxin-dependent reduction of the disulfide bond in the light. Alkylation of Cys-130 results in the inactivation of ATP synthesis. Belongs to the ATPase gamma chain family.