Glycan shield and epitope masking of a coronavirus spike protein observed by cryo-electron microscopy

By A. Walls, M. A. Tortorici, Brandon Frenz, Joost Snijder, Wentao Li, F. Rey, Frank DiMaio, B. Bosch, D. Veesler. 2016

393 citations recorded by the source corpus.

The threat of a major coronavirus pandemic urges the development of strategies to combat these pathogens. Human coronavirus NL63 (HCoV-NL63) is an α-coronavirus that can cause severe lower-respiratory-tract infections requiring hospitalization. We report here the 3.4-Å-resolution cryo-EM reconstruction of the HCoV-NL63 coronavirus spike glycoprotein trimer, which mediates entry into host cells and is the main target of neutralizing antibodies during infection. The map resolves the extensive glycan shield obstructing the protein surface and, in combination with mass spectrometry, provides a structural framework to understand the accessibility to antibodies. The structure reveals the complete architecture of the fusion machinery including the triggering loop and the C-terminal domains, which contribute to anchoring the trimer to the viral membrane. Our data further suggest that HCoV-NL63 and other coronaviruses use molecular trickery, based on epitope masking with glycans and activating conformational changes, to evade the immune system of infected hosts.

Subfields: Animal Science and Zoology, Infectious Diseases

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Animal Science and Zoology

1. D. Veesler
2. A. Walls
3. M. A. Tortorici
4. A. Tortoricia
5. David Veeslera
6. L. Enjuanes
7. Fang Li

In Infectious Diseases

1. D. Veesler
2. A. Walls
3. M. A. Tortorici
4. W. Hagen
5. A. Tortoricia
6. David Veeslera
7. Andrew T. McGuire
8. A. Wall

Citations in the corpus

• Elicitation of Potent Neutralizing Antibody Responses by Designed Protein Nanoparticle Vaccines for SARS-CoV-2 (2020, neutral): “, 1998) and for modulating accessibility to host proteases and neutralizing Abs (Walls et al., 2016b; 2017; 2019; Watanabe et al., 2020; Xiong et al., 2018; Yang et al., 2015).”
• Mapping Neutralizing and Immunodominant Sites on the SARS-CoV-2 Spike Receptor-Binding Domain by Structure-Guided High-Resolution Serology (2020, positive): “…and to its higher accessibility on the surface of virions and virus-infected cells, which is further enhanced by RBD opening and exposure of cryptic sites (Ke et al., 2020; Turo (cid:1) nova´ et al., 2020; Walls et al., 2020; Walls et al., 2016b; 2019; Watanabe et al., 2020; Wrapp et al., 2020).”
• Cryo-EM structures of MERS-CoV and SARS-CoV spike glycoproteins reveal the dynamic receptor binding domains (2017, neutral): “Recently, three pioneering studies on cryo-EM structures of the S ectodomain from MHV and hCoVs HKU1 and NL63 have revealed a similar overall structural fold of the full-length S protein 27–29 .”
• The human coronavirus HCoV-229E S-protein structure and receptor binding (2019, methodology): “Shielding the receptor binding site from immune recognition is one explanation for why the RBDs of some coronavirus S-proteins are found to access more than one conformation (Walls et al., 2016a; Gui et al., 2017) .”
• Structure, Function, and Antigenicity of the SARS-CoV-2 Spike Glycoprotein (2020, methodology): “As is the case for other b-coronavirus S glycoproteins, including SARS-CoV S (Gui et al., 2017; Kirchdoerfer et al., 2018; Pallesen et al., 2017; Park et al., 2019; Song et al., 2018; Tortorici et al., 2019;Walls et al., 2016a;Walls et al., 2016b;Walls et al., 2019; Yuan et al., 2017), the S1 subuni”
• Towards a solution to MERS: protective human monoclonal antibodies targeting different domains and functions of the MERS-coronavirus spike glycoprotein (2019, background): “Single-particle cryo-electron microscopic analyses of trimeric S ectodomains of several coronaviruses, including MERS-CoV [7] [8] [9] [10] [11] [12] [13] , revealed a multi-domain architecture of the S1 subunit, consisting of four core domains (designated A though D).”
• Identification of sialic acid-binding function for the Middle East respiratory syndrome coronavirus spike glycoprotein (2017, positive): “cryoelectron microscopy structures demonstrated that the spike N-terminal domains of the Alphacoronavirus HCoV-NL63 and betacoronaviruses murine hepatitis virus (MHV), HCoV-HKU1 and MERS-CoV display structural similarity (54, 55).”
• Vitrification after multiple rounds of sample application and blotting improves particle density on cryo-electron microscopy grids (2016, positive): “We used the mouse hepatitis virus (MHV) spike (S) glycoprotein ectodomain (Walls et al. 2016a; Walls et al 2016c) to illustrate the usefulness of our approach when vitrifying samples in presence of detergents (see Figure 5).”
• Glycan Shield and Fusion Activation of a Deltacoronavirus Spike Glycoprotein Fine-Tuned for Enteric Infections (2017, methodology): “Based on the 231 information gained from the HCoV-NL63 S structure(22), for which glycans appears to 232”
• Cryo-EM Structure of the 2019-nCoV Spike in the Prefusion Conformation (2020, background): “Like all 65 previously reported coronavirus S ectodomain structures, the density for 2019-nCoV S begins to 66 fade after the connector domain (CD), reflecting the flexibility of the heptad repeat 2 (HR2) 67 domain in the prefusion conformation (Supplementary Figure 4A) (13, 16-18).”