Cryo-EM Structures of the N501Y SARS-CoV-2 Spike Protein in Complex with ACE2 and Two Potent Neutralizing Antibodies

This article has been Reviewed by the following groups

Read the full article

Abstract

The recently reported “UK variant” of SARS-CoV-2 is thought to be more infectious than previously circulating strains as a result of several changes, including the N501Y mutation. We present a 2.9-Å resolution cryo-EM structure of the complex between the ACE2 receptor and N501Y spike protein ectodomains that shows Y501 inserted into a cavity at the binding interface near Y41 of ACE2. The additional interactions result in increased affinity of ACE2 for the N501Y mutant, accounting for its increased infectivity. However, this mutation does not result in large structural changes, enabling important neutralization epitopes to be retained in the spike receptor binding domain. We confirmed this through biophysical assays and by determining cryo-EM structures of spike protein ectodomains bound to two representative potent neutralizing antibody fragments.

Short summary

The N501Y mutation found in the coronavirus UK variant increases infectivity but some neutralizing antibodies can still bind.

Article activity feed

  1. SciScore for 10.1101/2021.01.11.426269: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    After washing, wells were incubated with either goat anti-human IgG (Jackson ImmunoResearch) or goat anti-Mouse IgG Fc Secondary Antibody, HRP (Invitrogen) at a 1:8,000 dilution in PBS-T + 0.5% BSA buffer for 1 h at room temperature.
    anti-human IgG
    suggested: None
    After washing, wells were incubated at a 1:8,000 dilution of Goat anti-Mouse IgG Fc Secondary Antibody, HRP (Invitrogen) in PBS-T + 0.5% BSA buffer for 1 h at room temperature.
    anti-Mouse IgG
    suggested: None
    For all experiments, controls for antibody–BSA interactions were performed.
    antibody–BSA
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    SARS-CoV-2 S and SARS_CoV-2 S N501Y pseudotyped retroviral particles were produced in HEK293T cells as described previously (29).
    HEK293T
    suggested: NCBI_Iran Cat# C498, RRID:CVCL_0063)
    For cell-entry and neutralization assays, HEK293T-ACE2 cells were seeded in 96-well plates at 50,000 cells per well.
    HEK293T-ACE2
    suggested: None
    Software and Algorithms
    SentencesResources
    For negative stain data, motion correction and CTF estimation were performed in RELION v.
    RELION
    suggested: (RELION, RRID:SCR_016274)
    For cryo-EM data, motion correction in patch mode (EER upsampling factor 1, EER number of fractions 40), CTF estimation in patch mode, reference-free particle picking, and particle extraction (extraction box size 640, Fourier crop to box size 320) were performed on-the-fly in cryoSPARC.
    cryoSPARC
    suggested: (cryoSPARC, RRID:SCR_016501)
    Initial models were first refined against sharpened locally refined maps, followed by iterative rounds of refinement against consensus map in COOT v.
    COOT
    suggested: (Coot, RRID:SCR_014222)
    Model validation was performed using MolProbity (33).
    MolProbity
    suggested: (MolProbity, RRID:SCR_014226)
    1.1.1 (34), and PyMOL (v.2.2 Schrodinger, LLC)
    PyMOL
    suggested: (PyMOL, RRID:SCR_000305)
    The IC50 values were calculated using a four-parameter dose-response (sigmoidal) curve in GraphPad Prism (version 9 for Windows, GraphPad Software, San Diego, California USA, www.graphpad.com).
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)
    GraphPad
    suggested: (GraphPad Prism, RRID:SCR_002798)
    The density maps reported will be made publicly available in the Electron Microscopy Data Bank (EMDB: https://www.ebi.ac.uk/pdbe/emdb/) and atomic coordinates for the structures will be available at the Protein Data Bank (PDB: https://www.rcsb.org).
    https://www.ebi.ac.uk/pdbe/emdb/
    suggested: (Electron Microscopy Data Bank at PDBe (MSD-EBI, RRID:SCR_006506)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).


    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: No clinical trial numbers were referenced.


    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.


    Results from JetFighter: Please consider improving the rainbow (“jet”) colormap(s) used on pages 32, 27, 29 and 31. At least one figure is not accessible to readers with colorblindness and/or is not true to the data, i.e. not perceptually uniform.


    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.