Ma Qinhong, Zhai Yufeng, Schneider Jane C, Ramseier Tom M, Saier Milton H
Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0116, USA.
Biochim Biophys Acta. 2003 Apr 1;1611(1-2):223-33. doi: 10.1016/s0005-2736(03)00059-2.
Gram-negative bacteria have evolved numerous systems for the export of proteins across their dual-membrane envelopes. Three of these systems (types I, III and IV) secrete proteins across both membranes in a single energy-coupled step. Four systems (Sec, Tat, MscL and Holins) secrete only across the inner membrane, and four systems [the main terminal branch (MTB), fimbrial usher porin (FUP), autotransporter (AT) and two-partner secretion families (TPS)] secrete only across the outer membrane. We have examined the genome sequences of Pseudomonas aeruginosa PAO1 and Pseudomonas fluorescens Pf0-1 for these systems. All systems except type IV were found in P. aeruginosa, and all except types III and IV were found in P. fluorescens. The numbers of each such system were variable depending on the system and species examined. Biochemical and physiological functions were assigned to these systems when possible, and the structural constituents were analyzed. Available information regarding the mechanisms of transport and energy coupling as well as physiological functions is summarized. This report serves to identify and characterize protein secretion systems in two divergent pseudomonads, one an opportunistic human pathogen, the other a plant symbiont.
革兰氏阴性菌已经进化出多种系统，用于将蛋白质输出穿过其双膜包膜。其中三种系统（I型、III型和IV型）在单一能量偶联步骤中跨两个膜分泌蛋白质。四种系统（Sec、Tat、MscL和孔蛋白）仅在内膜上分泌，还有四种系统[主要末端分支（MTB）、菌毛引导孔蛋白（FUP）、自转运蛋白（AT）和双伙伴分泌家族（TPS）]仅在外膜上分泌。我们研究了铜绿假单胞菌PAO1和荧光假单胞菌Pf0-1的基因组序列中的这些系统。除IV型外的所有系统都在铜绿假单胞菌中发现，除III型和IV型外的所有系统都在荧光假单胞菌中发现。每个此类系统的数量因所研究的系统和物种而异。在可能的情况下，为这些系统赋予了生化和生理功能，并对其结构成分进行了分析。总结了有关转运和能量偶联机制以及生理功能的现有信息。本报告旨在鉴定和表征两种不同假单胞菌中的蛋白质分泌系统，一种是机会性人类病原体，另一种是植物共生体。
