Filamentous phage infection:: crystal structure of g3p in complex with its coreceptor, the C-terminal domain of TolA
Filamentous phage infection:: crystal structure of g3p in complex with its coreceptor, the C-terminal domain of TolA
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DOI：
10.1016/s0969-2126(99)80092-6
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发表时间：
1999-06-15
期刊：
影响因子：
5.7
通讯作者：
Wlodawer, A
中科院分区：
文献类型：
--
作者：
Lubkowski, J;Hennecke, F;Wlodawer, A
背景资料：丝状Ff噬菌体（M13、fd和f1）感染雄性大肠杆菌细胞涉及噬菌体次要外壳基因3蛋白（g3 p）与细菌F菌毛（主要受体）的相互作用，随后与完整膜蛋白托拉（辅助受体）的相互作用。G3 p由三个结构域（N1、N2和CT）组成。N2结构域与F菌毛相互作用，而N1结构域-通过一个富含甘氨酸的柔性接头与N2连接，并在噬菌体上与之紧密相互作用-在感染过程的后期与托拉的C-末端结构域形成复合物。g3 p N1和托拉D3之间的复合物的晶体结构通过将这些结构域与长的柔性接头融合而获得，其在结构中不可见，表明其非常高的无序性，并且可能缺乏对复合物形成的干扰。这两个域之间的界面，对应于类似于1768埃（2）的掩埋分子表面，是明确界定的。尽管托拉D3和g3 p N2之间缺乏拓扑相似性，但这两个结构域都与g3 p N1结构域的相同区域相互作用。托拉D3的折叠不类似于任何先前已知的蛋白质motifs.Conclusions：这里呈现的融合蛋白的结构清楚地表明，在感染过程中，g3 p N2结构域被托拉D3结构域置换。g3 p N2和托拉D3的折叠是完全不同的，导致在它们与g3 p N1的复合物中观察到独特的结构域间接触。我们现在还可以解释g3 p N2结构域和F菌毛之间的相互作用如何使g3 p N1结构域与托拉形成复合物。
Background: Infection of male Escherichia coli cells by filamentous Ff bacteriophages (M13, fd, and f1) involves interaction of the phage minor coat gene 3 protein (g3p) with the bacterial F pilus (primary receptor), and subsequently with the integral membrane protein TolA (coreceptor). G3p consists of three domains (N1, N2, and CT). The N2 domain interacts with the F pilus, whereas the N1 domain - connected to N2 by a flexible glycine-rich linker and tightly interacting with it on the phage - farms a complex with the C-terminal domain of TolA at later stages of the infection process.Results: The crystal structure of the complex between g3p N1 and TolA D3 was obtained by fusing these domains with a long flexible linker, which was not visible in the structure, indicating its very high disorder and presumably a lack of interference with the formation of the complex. The interface between both domains, corresponding to similar to 1768 Angstrom(2) of buried molecular surface, is clearly defined. Despite the lack of topological similarity between TolA D3 and g3p N2, both domains interact with the same region of the g3p N1 domain. The fold of TolA D3 is not similar to any previously known protein motifs.Conclusions: The structure of the fusion protein presented here clearly shows that, during the infection process, the g3p N2 domain is displaced by the TolA D3 domain. The folds of g3p N2 and TolA D3 are entirely different, leading to distinctive interdomain contacts observed in their complexes with g3p N1. We can now also explain how the interactions between the g3p N2 domain and the F pilus enable the g3p N1 domain to form a complex with TolA.