Structure of an influenza C virus hemagglutinin-esterase-fusion (HEF2) intermediate

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.200 

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Snapshot of an influenza virus glycoprotein fusion intermediate.

Serrao, V.H.B.Cook, J.D.Lee, J.E.

(2021) Cell Rep 35: 109152-109152

  • DOI: https://doi.org/10.1016/j.celrep.2021.109152
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Enveloped virus entry requires the fusion of cellular and viral membranes, a process directed by their viral fusion glycoproteins. Our current knowledge of this process has been shaped by structural studies of the pre- and post-fusion conformations of these viral fusogens. These structural snapshots have revealed the start and end states necessary for fusion, but the dynamics of the intermediate conformations have remained unclear. Using the influenza C virus hemagglutinin-esterase-fusion glycoprotein as a model, we report the structural and biophysical characterization of a trapped intermediate. Crystallographic studies revealed a structural reorganization of the C terminus to create a second chain reversal region, resulting in the N and C termini being positioned in opposing directions. Intrinsic tryptophan fluorescence and bimane-induced quenching measurements suggest intermediate formation is mediated by conserved hydrophobic residues. Our study reveals a late-stage extended intermediate structural event. This work adds to our understanding of virus cell fusion.

  • Organizational Affiliation

    Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Hemagglutinin-esterase-fusion glycoprotein95Influenza C virus (C/Johannesburg/1/66)Mutation(s): 1 
Gene Names: HEFHE
Find proteins for P07975 (Influenza C virus (strain C/Johannesburg/1/1966))
Explore P07975 
Go to UniProtKB:  P07975
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP07975
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on CL

Download Ideal Coordinates CCD File 
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.200 
  • Space Group: P 21 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.142α = 90
b = 65.142β = 90
c = 65.142γ = 90
Software Package:
Software NamePurpose
Aimlessdata scaling
PDB_EXTRACTdata extraction
DIALSdata reduction

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Natural Sciences and Engineering Research Council (NSERC, Canada)CanadaRGPIN-2019-057
Canadian Institutes of Health Research (CIHR)CanadaMOP-115066

Revision History  (Full details and data files)

  • Version 1.0: 2021-05-19
    Type: Initial release
  • Version 1.1: 2021-06-02
    Changes: Database references
  • Version 1.2: 2023-10-18
    Changes: Data collection, Database references, Refinement description