Site-specific glycan analysis of the SARS-CoV-2 spike

TLDR

The SARS‑CoV‑2 spike protein, a trimeric glycoprotein targeted by vaccines, contains 22 N‑glycosylation sites per protomer, and the glycan composition can influence cell tropism and antibody epitope shielding. The authors expressed and purified recombinant glycosylated spike trimers, enzymatically cleaved them into single‑glycan peptides, and mapped each glycan site by mass spectrometry. This site‑specific glycan map serves as a benchmark for assessing antigen quality in vaccine and antibody test development. Watanabe et al.; Science, this issue, p.

Abstract

SARS-CoV-2 spike protein, elaborated Vaccine development for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is focused on the trimeric spike protein that initiates infection. Each protomer in the trimeric spike has 22 glycosylation sites. How these sites are glycosylated may affect which cells the virus can infect and could shield some epitopes from antibody neutralization. Watanabe et al. expressed and purified recombinant glycosylated spike trimers, proteolysed them to yield glycopeptides containing a single glycan, and determined the composition of the glycan sites by mass spectrometry. The analysis provides a benchmark that can be used to measure antigen quality as vaccines and antibody tests are developed. Science this issue p. 330