The Structure and Catalytic Mechanism of ATP Synthase

ATP synthase (F 1F o complex) is a key enzyme in energy conversion in all living organisms. During ATP synthesis, ATP synthase uses a proton gradient and the associated membrane potential to synthesize ATP. It can also catalyze the reverse reaction of ATP hydrolysis to generate a proton gradient. NMR, x ray analysis, genetics, chemical cross linking are combined and great progress in the understanding of the structure of the intact ATPase and its constituent subunits has been made. Among them, most works are focused on the ATP synthase of E.coli . The mechanism of converting an electrochemical gradient of protons or Na + ions across the membrane into rotational torque by the F o motor of the ATPase has been proposed by a two half channel or a one channel model. Binding change mechanism proposed by Boyer promoted greatly the understanding of the mechanism of the catalytic action of the F type ATP synthase. The mechanism of action of ATP synthase is controversial now. Some favor a tri site mechanism, where substrate must fill all three catalytic sites for activity, others a bi site mechanism, in which one of the three site is always unoccupied. The ATPase activity is also regulated by the conformational change of the enzyme complex or outside conditions. Our understanding of the functioning of ATP synthase have advanced dramatically, however, the mechanism of the ATP synthase is far from be fully understood and there are many challenges in the area.