van der Sluis Eli O, Driessen Arnold J M
Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9751 NN Haren, The Netherlands.
Trends Microbiol. 2006 Mar;14(3):105-8. doi: 10.1016/j.tim.2006.01.009. Epub 2006 Feb 21.
The Sec machinery facilitates the translocation of proteins across and into biological membranes. In several of the Proteobacteria, this machinery contains accessory features that are not present in any other bacterial division. The genomic distribution of these features in the context of bacterial phylogeny suggests that the Sec machinery has evolved in discrete steps. The canonical Sec machinery was initially supplemented with SecB; subsequently, SecE was extended with two transmembrane segments and, finally, SecM was introduced. The Sec machinery of Escherichia coli and other Enterobacteriales represents the end product of this stepwise evolution.
Sec转运机制促进蛋白质穿过并进入生物膜。在几种变形菌门细菌中，这种转运机制具有其他细菌门类所没有的辅助特征。这些特征在细菌系统发育背景下的基因组分布表明，Sec转运机制是逐步进化而来的。最初，典型的Sec转运机制增加了SecB；随后，SecE扩展出两个跨膜片段，最后引入了SecM。大肠杆菌和其他肠杆菌目的Sec转运机制代表了这一逐步进化的最终产物。
