White Stephen H, von Heijne Gunnar
Department of Physiology and Biophysics, Program in Macromolecular Structure, University of California at Irvine, Irvine, California 92697-4560, USA.
Curr Opin Struct Biol. 2004 Aug;14(4):397-404. doi: 10.1016/j.sbi.2004.07.003.
The SecY (bacteria) and Sec61 (eukaryotes) translocon complexes, or protein-conducting channels, work in concert with bound ribosomes to insert proteins into membranes during the first step of membrane protein assembly. The crystallographic structure of an archaeal SecY translocon provides dramatic new insights into the mechanism of translocon function. This structure suggests an explanation for how the translocon can aid in establishing membrane protein topology via the positive-inside rule. The folding of membrane proteins may begin in the ribosome exit tunnel, before entering the translocon, according to cryo-electron microscopy and biophysical studies.
细菌中的SecY和真核生物中的Sec61转位复合体，即蛋白质传导通道，在膜蛋白组装的第一步与结合的核糖体协同工作，将蛋白质插入膜中。古细菌SecY转位复合体的晶体结构为转位复合体的功能机制提供了全新的深刻见解。该结构为转位复合体如何通过正内规则帮助建立膜蛋白拓扑结构提供了解释。根据冷冻电子显微镜和生物物理研究，膜蛋白的折叠可能在进入转位复合体之前，在核糖体出口通道中就开始了。
