The structure of TolB, an essential component of the tol-dependent translocation system, and its protein-protein interaction with the translocation domain of colicin E9
The structure of TolB, an essential component of the tol-dependent translocation system, and its protein-protein interaction with the translocation domain of colicin E9
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DOI：
10.1016/s0969-2126(00)00079-4
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发表时间：
2000-01-15
期刊：
影响因子：
--
通讯作者：
Hemmings, AM
中科院分区：
文献类型：
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作者：
Carr, S;Penfold, CN;Hemmings, AM
背景：大肠杆菌素蛋白有三个功能域，每个功能域都涉及杀死大肠杆菌细胞的一个阶段：受体结合、易位和细胞毒性。中心(R)结构域负责受体结合活性，而n端(T)结构域介导易位，这是c端细胞毒性结构域从受体转运到其细胞毒性位点的过程。酶促E粘菌素如粘菌素E9的易位依赖于TolB，但该过程的细节尚不清楚。结果：我们利用酵母双杂交系统证明了大肠杆菌蛋白E9的T结构域和TolB之间的蛋白-蛋白相互作用，TolB是大肠杆菌中toll依赖易位系统的重要组成部分。原核色氨酸-天冬氨酸（WD）重复蛋白TolB的晶体结构揭示了一个基于五链混合β片的n端α + β结构域和一个c端六叶β螺旋桨结构域。结论：结果表明colicin ES T结构域的TolB-box残基与TolB的β -螺旋桨结构域相互作用。其他含有β -螺旋桨的蛋白质，酵母yPrp4蛋白和G蛋白的蛋白质-蛋白质相互作用是由螺旋桨叶片的环或外层膜介导的。确定T结构域-TolB复合物的三维结构以及分离TolB中取消与T结构域相互作用的突变将揭示TolB与E colicins的T结构域的蛋白-蛋白相互作用的细节。
Background: E colicin proteins have three functional domains, each of which is implicated in one of the stages of killing Escherichia coli cells: receptor binding, translocation and cytotoxicity. The central (R) domain is responsible for receptor-binding activity whereas the N-terminal (T) domain mediates translocation, the process by which the C-terminal cytotoxic domain is transported from the receptor to the site of its cytotoxicity. The translocation of enzymatic E colicins like colicin E9 is dependent upon TolB but the details of the process are not known.Results: We have demonstrated a protein-protein interaction between the T domain of colicin E9 and TolB, an essential component of the tol-dependent translocation system in E. coli, using the yeast two-hybrid system. The crystal structure of TolB, a procaryotic tryptophan-aspartate (WD) repeat protein, reveals an N-terminal alpha+beta domain based on a five-stranded mixed beta sheet and a C-terminal six-bladed beta-propeller domain.Conclusions: The results suggest that the TolB-box residues of the T domain of colicin ES interact with the beta-propeller domain of TolB. The protein-protein interactions of other beta-propeller-containing proteins, the yeast yPrp4 protein and G proteins, are mediated by the loops or outer sheets of the propeller blades. The determination of the three-dimensional structure of the T domain-TolB complex and the isolation of mutations in TolB that abolish the interaction with the T domain will reveal fine details of the protein-protein interaction of TolB and the T domain of E colicins.