Proton motive force drives the interaction of the inner membrane TolA and outer membrane Pal proteins in Escherichia coli
Proton motive force drives the interaction of the inner membrane TolA and outer membrane Pal proteins in Escherichia coli
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DOI：
10.1046/j.1365-2958.2000.02190.x
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发表时间：
2000-11-01
影响因子：
3.6
通讯作者：
Lloubès, R
中科院分区：
文献类型：
--
作者：
Cascales, E;Gavioli, M;Lloubès, R
大肠杆菌包膜的Tol-Pal系统由内膜TolQ、TolR和Tola蛋白、周质TolB蛋白和外膜Pal脂蛋白组成。Tol-Pal蛋白或主要脂蛋白(LPP)的任何缺陷都会导致外膜完整性丧失，导致药物和洗涤剂过敏、周质渗漏和外膜囊泡形成。我们发现，Tola的多拷贝质粒过量能够弥补LPP菌株的膜缺陷，但不能弥补PAL菌株的膜缺陷，这一结果表明，在PAL存在的情况下，过量表达的Tola具有稳定包膜的作用。我们通过体内交联和免疫沉淀实验证明了Pal和Tola形成了一种复合体。这些结果，加上对纯化的Pal和Tola衍生物的体外实验，使我们能够证明Pal与Tola的C末端结构域相互作用。我们还利用原载体、K+载体瓦林霉素、黑霉素、砷酸盐和发酵条件证明了质子动力与这种相互作用是耦合的。
The Tol-Pal system of the Escherichia coli envelope is formed from the inner membrane TolQ, TolR and TolA proteins, the periplasmic TolB protein and the outer membrane Pal lipoprotein. Any defect in the Tol-Pal proteins or in the major lipoprotein (Lpp) results in the loss of outer membrane integrity giving hypersensitivity to drugs and detergents, periplasmic leakage and outer membrane Vesicle formation. We found that multicopy plasmid overproduction of TolA was able to complement the membrane defects of an lpp strain but not those of a pal strain, This result indicated that overproduced TolA has an envelope-stabilizing effect when Pal is present. We demonstrate that Pal and TolA formed a complex using in vivo cross-linking and immunoprecipitation experiments. These results, together with in vitro experiments with purified Pal and TolA derivatives, allowed us to show that Pal interacts with the TolA C-terminal domain. We also demonstrate using protonophore, K+ carrier valinomycin, nigericin, arsenate and fermentative conditions that the proton motive force was coupled to this interaction.