The CF₀–CF₁ ATP synthase complex is a membrane-bound enzyme system present in the thylakoid membrane of chloroplasts and plays a central role in photophosphorylation during photosynthesis. It catalyzes the synthesis of ATP from ADP and inorganic phosphate by utilizing the proton motive force generated across the thylakoid membrane during the light reactions. Structurally and functionally, the complex is analogous to the F₀–F₁ ATP synthase of mitochondria but has distinct features adapted to the chloroplast environment. The complex consists of two major components: CF₀, which is embedded in the thylakoid membrane, and CF₁, which protrudes into the stroma. The CF₀ portion functions as the proton channel and is composed mainly of subunits I, II, and III (also referred to as subunits a, b, and c in some nomenclatures). Among these, subunit III forms a ring of multiple identical c-subunits that rotate within the membrane. CF₀ provides a pathway for protons to move from the thylakoid lumen, where protons accumulate during light-driven electron transport, into the stroma. The CF₁ portion is the catalytic domain responsible for ATP synthesis. It is a globular structure composed of five different subunits arranged in the stoichiometry α₃β₃γδε. The three β subunits contain the catalytic sites for ATP synthesis,