Structure of the Ebola virus glycoprotein spike within the virion envelope at 11\u2009\xc5 resolution

Daniel R Beniac,Timothy F Booth

doi:10.1038/srep46374

Daniel R Beniac, Timothy F Booth

Open Access

https://doi.org/10.1038/srep46374

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Abstract

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.

Highlights

Truncated mutants without a transmembrane domain, or as smaller sub-domains of the GP molecule, or as artificial virus-like particles (VLPs)[15,16,18,24,26,27,28,29]
Discrepancies had been observed between the structures of the entire, untruncated Ebola viruses (EBOVs) GP determined using material produced with differing heterologous expression systems, and between structures obtained using alternative tomographic or single-particle three-dimensional image processing methods 4,28
Viral filaments are frequently curved when prepared in the frozen-hydrated state for cryo-electron microscopy (Fig. 1b)

Summary

Introduction

Truncated mutants without a transmembrane domain, or as smaller sub-domains of the GP molecule, or as artificial virus-like particles (VLPs)[15,16,18,24,26,27,28,29]. 29,976 images were selected for reference-free analysis of the half-diameter of EBOV to investigate the spatial distribution of the GP spikes, as well as the periodicity and symmetrical relationships between GP and the matrix protein VP40 in the envelope, and the underlying nucleocapsid layer (Figs 1c and S3).

Results

Conclusion