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

Previous analyses of viral glycan shields have revealed the presence of underprocessed oligomannose-type glycans that seemingly arise due to steric constraints that prevent access of glycan processing enzymes to substrate glycans 29, 32, 33 , especially when the viral glycoprotein has evolved to mask immunogenic epitopes with a particularly dense array of host-derived glycans 31, 34 . Restricted access to these glycan sites or interference with surrounding protein surface or neighbouring glycan residues can render glycan processing enzymes ineffective in specific regions 32, 33, 35 . Glycan processing on soluble glycoproteins has also been shown to be a strong reporter of native-like protein architecture and thus immunogen . CC-BY 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.02.20.957472 doi: bioRxiv preprint integrity [36] [37] [38] ; and glycan processing on a successful immunogen candidate should therefore mimic, as closely as possible, the structural features observed on the native virus 39, 40 .