Clavel T, Germon P, Vianney A, Portalier R, Lazzaroni J C
Laboratoire de Microbiologie et Génétique Moléculaire, CNRS-Université Lyon I, Villeurbanne, France.
Mol Microbiol. 1998 Jul;29(1):359-67. doi: 10.1046/j.1365-2958.1998.00945.x.
The Tol-Pal proteins of Escherichia coli are involved in maintaining outer membrane integrity. Transmembrane domains of TolQ, TolR and TolA interact in the cytoplasmic membrane, while TolB and Pal form a complex near the outer membrane. TolB and the central domain of TolA interact in vitro with the outer membrane porins. In this study, both genetic and biochemical analyses were carried out to analyse the links between TolB, Pal and other components of the cell envelope. It was shown that TolB could be cross-linked in vivo with Pal, OmpA and Lpp, while Pal was associated with TolB and OmpA. The isolation of pal and tolB mutants disrupting some interactions between these proteins represents at first approach to characterizing the residues contributing to the interactions. We propose that TolB and Pal are part of a multiprotein complex that links the peptidoglycan to the outer membrane. The Tol-Pal proteins might form transenvelope complexes that bring the two membranes into close proximity and help some outer membrane components to reach their final destination.
大肠杆菌的Tol-Pal蛋白参与维持外膜完整性。TolQ、TolR和TolA的跨膜结构域在细胞质膜中相互作用，而TolB和Pal在外膜附近形成复合物。TolB和TolA的中央结构域在体外与外膜孔蛋白相互作用。在本研究中，进行了遗传和生化分析，以分析TolB、Pal与细胞壁其他成分之间的联系。结果表明，TolB在体内可与Pal、OmpA和Lpp交联，而Pal与TolB和OmpA相关联。分离破坏这些蛋白质之间某些相互作用的pal和tolB突变体是表征有助于相互作用的残基的初步方法。我们提出，TolB和Pal是将肽聚糖与外膜连接起来的多蛋白复合物的一部分。Tol-Pal蛋白可能形成跨包膜复合物，使两个膜紧密靠近，并帮助一些外膜成分到达其最终目的地。
