Coupling Mechanism between Proton Transport and ATP Synthesis in Chloroplasts

Abstract

ATP synthesis from ADP and phosphate is a process in need of energy which is made feasible by coupling to transmembrane H⁺ translocation down the H⁺ gradient, the coupling membrane in chloroplasts being the thylakoid membrane and the coupling device being a membrane protein called ATP-synthase. Direction of H⁺ translocation to drive ATP synthesis is from the inside to the outside water phase of the thylakoid vesicles (see Fig. 1). The aim of our work is to get insight into the coupling process at the ATP-synthase by analysis of the kinetical pattern as controlled by transmembrane ΔpH.