SARS-CoV-2.rar

The glycoprotein spike (S) on the surface of SARS-CoV-2
is a determinant for viral invasion and host immune response. Herein, we
characterized the site-specific N-glycosylation of S protein at the level of
intact glycopeptides. All 22 potential N-glycosites were identified in the S-protein
protomer and were found to be preserved among the 753 SARS-CoV-2 genome
sequences. The glycosites
exhibited glycoform heterogeneity as expected for a human
cell-expressed protein subunits. We identified
masses that correspond to 157 N-glycans, primarily of the complex
type. In contrast, the insect cell-expressed S protein contained 38 N-glycans, completely
of the high-mannose type. Our
results revealed that the N-glycosylation of S protein was regularly occurred
on each site and the glycan types were highly determined by the differential
processing of N-glycans among human and insect cells, regardless of the
location of glycosites, although N-glycans were diverse and heterogenous on
each site. Moreover, the N-glycan compositions were conserved among different
sizes of subunits. This N-glycosylation landscape and the differential N-glycan patterns among
distinct host cells are expected to shed light on the infection mechanism and present
a positive view for the development of vaccines and targeted drugs.