Abstract
Extensive glycosylation of the spike protein of severe acute respiratory syndrome coronavirus 2 virus not only shields the major part of it from host immune responses, but glycans at specific sites also act on its conformation dynamics and contribute to efficient host receptor binding, and hence infectivity. As variants of concern arise during the course of the coronavirus disease of 2019 pandemic, it is unclear if mutations accumulated within the spike protein would affect its site-specific glycosylation pattern. The Alpha variant derived from the D614G lineage is distinguished from others by having deletion mutations located right within an immunogenic supersite of the spike N-terminal domain (NTD) that make it refractory to most neutralizing antibodies directed against this domain. Despite maintaining an overall similar structural conformation, our mass spectrometry-based site-specific glycosylation analyses of similarly produced spike proteins with and without the D614G and Alpha variant mutations reveal a significant shift in the processing state of N-glycans on one specific NTD site. Its conversion to a higher proportion of complex type structures is indicative of altered spatial accessibility attributable to mutations specific to the Alpha variant that may impact its transmissibility. This and other more subtle changes in glycosylation features detected at other sites provide crucial missing information otherwise not apparent in the available cryogenic electron microscopy-derived structures of the spike protein variants.
Keywords: SARS-CoV-2; cryo-EM; mass spectrometry; site-specific glycosylation.
【저자키워드】 SARS-CoV-2, mass spectrometry, cryo-EM, site-specific glycosylation., 【초록키워드】 coronavirus disease, neutralizing antibody, Structure, coronavirus, mass spectrometry, pandemic, Mutation, Neutralizing antibodies, glycosylation, variants of concern, severe acute respiratory syndrome Coronavirus, virus, variants, Spike protein, glycans, Transmissibility, immune responses, Lineage, D614G, cryo-EM, NTD, Alpha variant, information, glycan, binding, N-terminal domain, Analysis, Spike proteins, N-glycan, acute respiratory syndrome, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, host receptor, complex, domain, host immune responses, immunogenic, cryo, Affect, N-glycans, feature, Course, produced, proportion, changes in, contribute, the spike protein, accumulated, Extensive, 【제목키워드】 Mutation, glycosylation, SARS-CoV-2 spike protein, arising,