Site-specific N-glycosylation Characterization of Recombinant SARS-CoV-2 Spike Proteins using High-Resolution Mass Spectrometry

Yong Zhang; Wanjun Zhao; Yonghong Mao; Shisheng Wang; Yi Zhong; Tao Su; Meng Gong; Xiaofeng Lu; Jingqiu Cheng; Hao Yang

Therefore, we posit that the glycan coverage on the SARS-CoV-2 S protein could leave relatively accessible antigens and epitopes, although the complex N-glycans might mask some surface immunogens. These features may provide a promising . CC-BY-NC-ND 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 It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the .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/10.1101/2020.03.28.013276 doi: bioRxiv preprint landscape on the SARS-CoV-2 S protein for immune recognition. This potential is bolstered by the findings that the convalescent sera from COVID-19 patients contains antibodies against the SARS-CoV-2 S protein (7) . A previous study on SARS-CoV has revealed that the oligomannose on the S protein can be recognized by The remarkable heterogeneity of N-glycosylation in the S protein subunit expressed in human cells was revealed in our study (Fig. 3F) . By contrast, the N-glycosylation of the S protein subunit in insect cells showed less heterogeneity and complexity than that of human cell-derived proteins (Fig. 3E) . Moreover, the site-specific glycan occupancy tended to be identical in the same host cell, regardless of protein length ( Fig. 4D and 4E) . These results indicate the N-glycan compositions and types on S protein largely attribute to different host cells with the differential processing . CC-BY-NC-ND 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 It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the .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/10.1101/2020.03.28.013276 doi: bioRxiv preprint pathways of glycosylation. We can expect that the native N-glycosylation profile of the SARS-CoV-2 S protein in humans tends to be consistent with that of the recombinant protein expressed in human cells, unless the virus buds off early in the glycosylation processing pathway and produces immature glycans (19, 27, 35) .