Vulnerabilities in coronavirus glycan shields despite extensive glycosylation

Yasunori Watanabe; Zachary T. Berndsen; Jayna Raghwani; Gemma E. Seabright; Joel D. Allen; Jason S. McLellan; Ian A. Wilson; Thomas A. Bowden; Andrew B. Ward; Max Crispin

We then investigated the glycan shield densities of seven viral class I fusion proteins using a global structural approach which was calculated by dividing the number of amino-acids that interact with glycans by the number of solvent-accessible amino-acid residues of each respective glycoprotein and plotted this against oligomannose abundance. A strong correlation was observed (Fig. 6 ) and viruses historically classified as "evasion strong" 59 had significantly elevated glycan shield densities and oligomannose abundance, which underscores the importance of glycan shielding in immune evasion. Fig. 5 ). The number of amino-acid residues interacting with N-linked glycans was divided by the number of solventaccessible amino-acid residues of the glycoprotein as a measure for global glycan shield density. All viral glycoproteins analysed were expressed as trimers in HEK 293F cells apart from LASV GPC, which was derived from virus-like particles from Madin-Darby canine kidney II cells.