Preprint Article Version 2 This version is not peer-reviewed

Identification of 22 N-glycosites on Spike Glycoprotein of SARS-CoV-2 and Accessible Surface Glycopeptide Motifs: Implications on Vaccination and Antibody Therapeutics

Version 1 : Received: 24 February 2020 / Approved: 25 February 2020 / Online: 25 February 2020 (13:44:15 CET)
Version 2 : Received: 12 April 2020 / Approved: 13 April 2020 / Online: 13 April 2020 (11:09:29 CEST)

How to cite: Zhou, D.; Qi, R.; Zhang, W.; Tian, X.; Peng, C. Identification of 22 N-glycosites on Spike Glycoprotein of SARS-CoV-2 and Accessible Surface Glycopeptide Motifs: Implications on Vaccination and Antibody Therapeutics. Preprints 2020, 2020020381 (doi: 10.20944/preprints202002.0381.v2). Zhou, D.; Qi, R.; Zhang, W.; Tian, X.; Peng, C. Identification of 22 N-glycosites on Spike Glycoprotein of SARS-CoV-2 and Accessible Surface Glycopeptide Motifs: Implications on Vaccination and Antibody Therapeutics. Preprints 2020, 2020020381 (doi: 10.20944/preprints202002.0381.v2).

Abstract

Corona viruses hijack human enzymes to assembly sugar coat on Spike glycoproteins. The mechanism that human antibodies may uncover the antigenic viral peptide epitopes hidden by sugar coat are unknown. In this study, we analyzed recombinant SARS-CoV-2 Spike protein secreted from BTI-Tn-5B1-4 cells, by trypsin and chymotrypsin digestion followed by mass spectrometry analysis. We acquired MS/MS spectrums for glycopeptides of all 22 predicted N-glycosylated sites. We further analyzed the surface accessibility of Spike proteins according to Cryo-EM and homolog-modeled structures, and available antibodies that bind to SARS-CoV-1. The results showed that all 22 N-glycosylated sites of SARS-CoV-2 are modified by high-mannose type of N-glycans. MS/MS fragmentation clearly established the glycopeptide identities. Electron densities of glycans cover most of the Spike receptor binding domain of SARS-CoV-2, except YQAGSTPCNGVEGFNCYFPLQSYGFQPTNGVGYQ, similar to a region FSPDGKPCTPPALNCYWPLNDYGFYTTTGIGYQ in SARS-CoV-1. Other surface-exposed domains included those located on Central Helix, between amino acids 967 and 1016 of SARS-CoV-1, and 985 to 1034 of SARS-CoV-2 Spike protein. As the majority of antibody paratopes bind to peptide portion with or without sugar modification, we propose a snake-catcher model that a minimal length of peptide is first clamped by a paratope, and the binding is either strengthened by sugars close to peptide, or not interfered by sugar modification.

Subject Areas

SARS-CoV2; corona virus; glycopeptide; N-linked glycans; mass spectrometry; antibody; cryo-EM structure; crystal structures; epitope prediction

Comments (1)

Comment 1
Received: 13 April 2020
Commenter: Dapeng Zhou
Commenter's Conflict of Interests: Author
Comment: Mass spectrometry data have been added.
Two new authors have been added.
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