Viral Diseases Division, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, R3E 3P6, Canada.
Department of Medical Microbiology and Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, R3E 0W3, Canada.
Sci Rep. 2017 Apr 11;7:46374. doi: 10.1038/srep46374.
We present the structure of the surface Ebola virus (EBOV) trimeric glycoprotein (GP) spike at 11 Å resolution, in situ within the viral plasma membrane of purified virus particles. GP functions in cellular attachment, endosomal entry, and membrane fusion to initiate infection, and is a key therapeutic target. Nevertheless, only about half of the GP molecule has yet been solved to atomic resolution, excluding the mucin-like and transmembrane domains, and some of the glycans. Fitting of the atomic resolution X-ray data from expressed, truncated deletion constructs within our 11 Å structure of the entire molecule demonstrates the relationship between the GP1-GP2 domains, the mucin-like and transmembrane domains, and the bilaminar lipid envelope. We show that the mucin-like domain covers the glycan cap and partially occludes the receptor binding sites prior to proteolytic cleavage. Our structure is also consistent with key antibody neutralisation sites on GP being accessible prior to proteolysis. Based on the findings of us and others, GP-mediated binding may create an angle of 18 degrees between the planes of viral and endosomal membranes.
我们展示了在 11Å 分辨率下，位于纯化病毒粒子的病毒质膜中的表面埃博拉病毒（EBOV）三聚体糖蛋白（GP）刺突的结构。GP 在细胞附着、内体进入和膜融合中发挥作用，从而引发感染，是关键的治疗靶点。然而，到目前为止，只有大约一半的 GP 分子已经被解析到原子分辨率，不包括粘蛋白样和跨膜结构域，以及一些聚糖。在我们解析的整个分子的 11Å 结构中，用表达的、截短的缺失构建体拟合原子分辨率的 X 射线数据，证明了 GP1-GP2 结构域、粘蛋白样和跨膜结构域以及双层脂质包膜之间的关系。我们表明，在蛋白水解切割之前，粘蛋白样结构域覆盖聚糖帽并部分遮挡受体结合位点。我们的结构也与 GP 上关键的抗体中和位点在蛋白水解切割之前可及的发现相一致。基于我们和其他人的研究结果，GP 介导的结合可能会在病毒和内体膜之间形成 18 度的夹角。
