ATP合酶的结构与催化机理

ATP合酶 (F1Fo 复合物) 是生物体内进行氧化磷酸化和光合磷酸化的关键酶.随着核磁共振、X射线晶体衍射、遗传学、化学交联等技术在ATP合酶研究中的广泛应用,ATP合酶的整体结构及其各组成亚基结构的研究都有很大的进展.其中细菌ATP合酶结构的研究更为深入.目前对质子通过Fo的转运方式提出两种模型:单通道和双半通道模型.对扭力矩的形成以及旋转催化也有了进一步的认识.Boyer提出的结合改变机理推动了ATP合酶催化机制的研究,现在主要有两点催化机制和三点催化机制.ATP合酶的催化反应受酶的构象变化和外在条件的调节.

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.