Haltia T, Freire E
Department of Biology, Johns Hopkins University, Baltimore, MD 21218.
Biochim Biophys Acta. 1995 Feb 14;1228(1):1-27. doi: 10.1016/0005-2728(94)00161-w.
While a considerable amount of literature deals with the structural energetics of water-soluble proteins, relatively little is known about the forces that determine the stability of membrane proteins. Similarly, only a few membrane protein structures are known at atomic resolution, although new structures have recently been described. In this article, we review the current knowledge about the structural features of membrane proteins. We then proceed to summarize the existing literature regarding the thermal stability of bacteriorhodopsin, cytochrome-c oxidase, the band 3 protein, Photosystem II and porins. We conclude that a fundamental difference between soluble and membrane proteins is the high thermal stability of intrabilayer secondary structure elements in membrane proteins. This property manifests itself as incomplete unfolding, and is reflected in the observed low enthalpies of denaturation of most membrane proteins. By contrast, the extramembranous parts of membrane proteins may behave much like soluble proteins. A brief general account of thermodynamics factors that contribute to the stability of water soluble and membrane proteins is presented.
尽管有大量文献涉及水溶性蛋白质的结构能量学，但对于决定膜蛋白稳定性的作用力却知之甚少。同样，尽管最近有新的结构被描述，但只有少数膜蛋白结构是在原子分辨率下已知的。在本文中，我们综述了关于膜蛋白结构特征的当前知识。然后我们继续总结关于细菌视紫红质、细胞色素c氧化酶、带3蛋白、光系统II和孔蛋白热稳定性的现有文献。我们得出结论，可溶性蛋白和膜蛋白之间的一个根本区别在于膜蛋白双层内二级结构元件的高热稳定性。这种特性表现为不完全展开，并反映在大多数膜蛋白观察到的低变性焓中。相比之下，膜蛋白的膜外部分可能表现得与可溶性蛋白非常相似。本文简要概述了有助于水溶性蛋白和膜蛋白稳定性的热力学因素。
