Senior A E
Department of Biochemistry, University of Rochester, New York 14642.
Annu Rev Biophys Biophys Chem. 1990;19:7-41. doi: 10.1146/annurev.bb.19.060190.000255.
The purpose of this review is to provide an up-to-date summary of E. coli proton-translocating F1F0ATPase. From work on this enzyme, new insights have been gained in the areas of bacterial physiology and energy metabolism, mechanism of enzyme action, mechanism of ion transport through membranes, structure of membrane proteins, mechanism of energy coupling, and regulation of complex enzyme expression and assembly. An important and pressing need is for more structural information. High-resolution structural analyses of F1F0 have not progressed far, and this is likely to present a road block unless overcome. One possibility is to crystallize or apply nuclear magnetic resonance spectroscopy to isolated subunits available in native form from E. coli F1F0. In this way, one might incrementally build a structure of the F1F0 complex. Static views, however, are unlikely to provide a complete picture of a dynamic enzyme such as this, in which long-range interactions between F0 and F1 and cooperative interactions between nucleotide-binding sites play such an important role in catalysis. Mutagenesis and reversion analysis are two powerful techniques, which, combined with direct enzymological measurements, can be exploited in the immediate future to study the intriguing dynamic aspects of F1F0 function. Many questions remain to challenge us. Regulation of enzyme activity in the cell is not understood. The role of the noncatalytic nucleotide sites is unknown. The assembly pathway and regulation of expression are not established. The mechanisms of H+ translocation and catalysis seem to be proving amenable to analysis, and further advances in these areas can be expected. Long-range conformational interaction between the H+ conduction machinery in F0 and the catalytic sites in F1 seems basic to energy coupling; a major future goal is to provide a realistic physical explanation to validate this concept.
本综述的目的是提供关于大肠杆菌质子转运F1F0ATP酶的最新总结。通过对该酶的研究，在细菌生理学和能量代谢、酶作用机制、离子跨膜运输机制、膜蛋白结构、能量偶联机制以及复合酶表达和组装调控等领域获得了新的见解。一个重要且紧迫的需求是获取更多的结构信息。F1F0的高分辨率结构分析进展不大，若不克服这一点，很可能会成为障碍。一种可能性是将从大肠杆菌F1F0以天然形式获得的分离亚基进行结晶或应用核磁共振光谱法。通过这种方式，或许可以逐步构建F1F0复合物的结构。然而，静态的观点不太可能完整呈现这样一种动态酶的全貌，在这种酶中，F0和F1之间的远程相互作用以及核苷酸结合位点之间的协同相互作用在催化过程中起着如此重要的作用。诱变和回复分析是两种强大的技术，结合直接的酶学测量，在不久的将来可用于研究F1F0功能中有趣的动态方面。仍有许多问题有待我们去攻克。细胞中酶活性的调控尚不明确。非催化性核苷酸位点的作用未知。组装途径和表达调控尚未确立。H+转运和催化机制似乎易于分析，预计在这些领域会有进一步进展。F0中的H+传导机制与F1中的催化位点之间的远程构象相互作用似乎是能量偶联的基础；未来的一个主要目标是提供一个合理的物理解释来验证这一概念。
