Real-Time Analysis of Individual Ebola Virus Glycoproteins Reveals Pre-Fusion, Entry-Relevant Conformational Dynamics
Real-Time Analysis of Individual Ebola Virus Glycoproteins Reveals Pre-Fusion, Entry-Relevant Conformational Dynamics
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DOI：
10.3390/v12010103
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发表时间：
2020-01-01
期刊：
影响因子：
4.7
通讯作者：
Munro, James B.
中科院分区：
文献类型：
--
作者：
Durham, Natasha D.;Howard, Angela R.;Munro, James B.
埃博拉病毒（EBOV）包膜糖蛋白（GP）在感染期间介导病毒体膜与易感靶细胞膜的融合。虽然GP的内体组织蛋白酶的蛋白水解裂解和细胞受体尼曼-匹克C1蛋白（NPC 1）的结合是病毒进入的必要步骤，这些事件促进膜融合的详细机制仍然未知。在这里，我们应用单分子Forster共振能量转移（smFRET）成像来研究EBOV GP三聚体胞外域的结构动力学，以及假病毒体表面上的功能性跨膜蛋白。我们表明，在这两种情况下，融合前GP是动态的，并采样多种构象。聚糖帽的去除和NPC 1结合改变了构象平衡，表明与病毒融合相关的构象稳定。此外，几种中和抗体丰富了替代构象状态。这表明这些抗体通过限制与融合相关的GP构象的接近来中和EBOV。这项工作证明了先前未观察到的融合前EBOV GP的动力学，并为GP功能和抗体介导的中和的研究提供了对构象变化具有高度敏感性的平台。
The Ebola virus (EBOV) envelope glycoprotein (GP) mediates the fusion of the virion membrane with the membrane of susceptible target cells during infection. While proteolytic cleavage of GP by endosomal cathepsins and binding of the cellular receptor Niemann-Pick C1 protein (NPC1) are essential steps for virus entry, the detailed mechanisms by which these events promote membrane fusion remain unknown. Here, we applied single-molecule Forster resonance energy transfer (smFRET) imaging to investigate the structural dynamics of the EBOV GP trimeric ectodomain, and the functional transmembrane protein on the surface of pseudovirions. We show that in both contexts, pre-fusion GP is dynamic and samples multiple conformations. Removal of the glycan cap and NPC1 binding shift the conformational equilibrium, suggesting stabilization of conformations relevant to viral fusion. Furthermore, several neutralizing antibodies enrich alternative conformational states. This suggests that these antibodies neutralize EBOV by restricting access to GP conformations relevant to fusion. This work demonstrates previously unobserved dynamics of pre-fusion EBOV GP and presents a platform with heightened sensitivity to conformational changes for the study of GP function and antibody-mediated neutralization.