Structural intermediates in the fusion-associated transition of vesiculovirus glycoprotein
Structural intermediates in the fusion-associated transition of vesiculovirus glycoprotein
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DOI：
10.15252/embj.201694565
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发表时间：
2017-03-01
期刊：
影响因子：
11.4
通讯作者：
Gaudin, Yves
中科院分区：
文献类型：
--
作者：
Baquero, Eduard;Albertini, Aurelie A.;Gaudin, Yves
水泡病毒通过膜融合进入细胞，由融合糖蛋白G中的大的、低pH诱导的构象变化驱动，所述构象变化涉及通过单体中间体从三聚体融合前状态向三聚体融合后状态的转变。在这里，我们提出了G融合蛋白的结构在中间pH值的水泡性口炎病毒（VSV）和Chandipura病毒（CHAV），这是负责致命的脑病。首先，CHAV G晶体结构显示形成异二聚体的扁平二聚体的两种中间构象。在病毒体上，电子显微镜（EM）和断层扫描显示类似于晶体构象之一的单体刺突。在溶液中，质谱显示G.最后，二聚体界面处的突变，涉及以反平行方式缔合以形成分子间片层的融合结构域，影响G融合特性。恢复融合活性的补偿突变的位置强烈表明，该接口是功能相关的。这项工作揭示了G结构变化的范围，并表明G单体可以重新关联，通过融合结构域之间的反平行相互作用，成为在融合过程的早期阶段发挥作用的二聚体。
Vesiculoviruses enter cells by membrane fusion, driven by a large, low-pH-induced, conformational change in the fusion glycoprotein G that involves transition from a trimeric pre-fusion toward a trimeric post-fusion state via monomeric intermediates. Here, we present the structure of the G fusion protein at intermediate pH for two vesiculoviruses, vesicular stomatitis virus (VSV) and Chandipura virus (CHAV), which is responsible for deadly encephalopathies. First, a CHAV G crystal structure shows two intermediate conformations forming a flat dimer of heterodimers. On virions, electron microscopy (EM) and tomography reveal monomeric spikes similar to one of the crystal conformations. In solution, mass spectrometry shows dimers of G. Finally, mutations at a dimer interface, involving fusion domains associated in an antiparallel manner to form an intermolecular -sheet, affect G fusion properties. The location of the compensatory mutations restoring fusion activity strongly suggests that this interface is functionally relevant. This work reveals the range of G structural changes and suggests that G monomers can re-associate, through antiparallel interactions between fusion domains, into dimers that play a role at some early stage of the fusion process.