Organisation of the orthobunyavirus tripodal spike and the structural changes induced by low pH and K+ during entry
Year: 2023
Type: article
Abstract: Following endocytosis, enveloped viruses employ the changing environment of maturing endosomes as cues to promote endosomal escape, a process often mediated by viral glycoproteins. We previously showed that both high [K + ] and low pH promote entry of Bunyamwera virus (BUNV), the prototypical bunyavirus. Here, we use sub-tomogram averaging and AlphaFold, to generate a pseudo-atomic model of the whole BUNV glycoprotein envelope. We unambiguously locate the Gc fusion domain and its chaperone Gn within the floor domain of the spike. Furthermore, viral incubation at low pH and high [K + ], reminiscent of endocytic conditions, results in a dramatic rearrangement of the BUNV envelope. Structural and biochemical assays indicate that pH 6.3/K + in the absence of a target membrane elicits a fusion-capable triggered intermediate state of BUNV GPs; but the same conditions induce fusion when target membranes are present. Taken together, we provide mechanistic understanding of the requirements for bunyavirus entry.
Source: Nature Communications
Language: English
Topic: Virology and Viral Diseases
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $6,290
Awards: G1443984021, New infrastructure for EM studies at the University of Leeds., G2088419574, G2784879147, G3702837198, G4232259350, G4465978615, G4538406725, Modern Cryo-Electron Microscopy with Direct Electron Detection at the University of Leeds., Essential ionic triggers for enveloped virus entry, G6666940659, State of the art direct electron detection at the Astbury Biostructure Laboratory, Modern Cryo-Electron Microscopy with Direct Electron Detection at the University of Leeds., G821027576, Understanding the catalytic and non-catalytic roles of the essential 3D protein in the FMDV replication complex
OpenAlex ID: W4386923313