Structural characterization of the SARS-coronavirus spike S fusion protein core.
Structural characterization of the SARS-coronavirus spike S fusion protein core.
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DOI：
10.1074/jbc.m400759200
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发表时间：
2004-05-14
期刊：
影响因子：
--
通讯作者：
Hodges RS
中科院分区：
文献类型：
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作者：
Tripet B;Howard MW;Jobling M;Holmes RK;Holmes KV;Hodges RS
冠状病毒的刺突糖蛋白介导病毒进入宿主细胞。它是一种1型病毒融合蛋白，其特征是包含两个七核苷酸重复区域，分别表示为HR-N和HR-C，在蛋白质的外畴内形成螺旋状结构。先前的研究表明，两个七肽重复区可以经历从其天然状态到6螺旋束（三聚体或二聚体）的构象变化，从而介导病毒和宿主细胞膜的融合。在这里，我们描述了严重急性呼吸综合征冠状病毒S蛋白中两个预测的七核苷酸重复区域的生物物理分析。结果表明，在分离状态下，HR-N区形成稳定的α-螺旋螺旋状线圈，以四聚体状态结合。隔离的HR-C区形成弱稳定的三聚体线圈。当混合在一起时，两个肽区（HR-N和HR-C）结合形成非常稳定的α-螺旋6链结构（异源二聚体的三聚体）。系统肽图谱显示，HR-N与HR-C区相互作用的位点位于HR-N的916 ~ 950残基和HR-C的1151 ~ 1185残基之间。此外，链间二硫桥实验表明，配合物中HR-N和HR-C螺旋的相对取向是反平行的。总的来说，异链复合物的结构与其他1型病毒融合蛋白在融合能力状态下观察到的结构一致。
The spike (S) glycoprotein of coronaviruses mediates viral entry into host cells. It is a type 1 viral fusion protein that characteristically contains two heptad repeat regions, denoted HR-N and HR-C, that form coiled-coil structures within the ectodomain of the protein. Previous studies have shown that the two heptad repeat regions can undergo a conformational change from their native state to a 6-helix bundle (trimer of dimers), which mediates fusion of viral and host cell membranes. Here we describe the biophysical analysis of the two predicted heptad repeat regions within the severe acute respiratory syndrome coronavirus S protein. Our results show that in isolation the HR-N region forms a stable α-helical coiled coil that associates in a tetrameric state. The HR-C region in isolation formed a weakly stable trimeric coiled coil. When mixed together, the two peptide regions (HR-N and HR-C) associated to form a very stable α-helical 6-stranded structure (trimer of heterodimers). Systematic peptide mapping showed that the site of interaction between the HR-N and HR-C regions is between residues 916–950 of HR-N and residues 1151–1185 of HR-C. Additionally, interchain disulfide bridge experiments showed that the relative orientation of the HR-N and HR-C helices in the complex was antiparallel. Overall, the structure of the hetero-stranded complex is consistent with the structures observed for other type 1 viral fusion proteins in their fusion-competent state.