Gold Vicki A M, Duong Franck, Collinson Ian
Department of Biochemistry, University of Bristol, Bristol, UK.
Mol Membr Biol. 2007 Sep-Dec;24(5-6):387-94. doi: 10.1080/09687680701416570.
Bacteria and archaea possess a protein complex in the plasma membrane that governs protein secretion and membrane protein insertion. Eukaryotes carry homologues in the endoplasmic reticulum (ER) where they direct the same reaction. A combination of experiments conducted on the systems found in all three domains of life has revealed a great deal about protein translocation. The channel provides a route for proteins to pass through the hydrophobic barrier of the membrane, assisted by various partner proteins which maintain an unfolded state of the substrate, target it to the channel and provide the energy and mechanical drive required for transport. In bacteria, the post-translational reaction utilizes an ATPase that couples the free energy of ATP binding and hydrolysis to move the substrate through the protein pore. This review will draw on genetic, biochemical and structural findings in an account of our current understanding of this mechanism.
细菌和古菌在质膜中拥有一种蛋白质复合物，该复合物控制蛋白质分泌和膜蛋白插入。真核生物在内质网（ER）中具有同源物，它们在内质网中指导相同的反应。对生命所有三个域中发现的系统进行的一系列实验揭示了大量有关蛋白质转运的信息。该通道为蛋白质穿过膜的疏水屏障提供了一条途径，各种伴侣蛋白协助蛋白质转运，这些伴侣蛋白维持底物的未折叠状态，将其靶向通道，并提供转运所需的能量和机械驱动力。在细菌中，翻译后反应利用一种ATP酶，该酶将ATP结合和水解的自由能耦合起来，以推动底物穿过蛋白质孔。本综述将借鉴遗传学、生物化学和结构学方面的研究成果，阐述我们目前对这一机制的理解。
