Glycosylation profiling of monkeypox virus structural proteins with poly Ser-Arg materials†

Although the glycosylation of viral proteins plays a critical role in the process of viral invasion into host cells, studies on the glycosylation of monkeypox virus (MPXV) structural proteins have not yet been reported. To investigate the importance of MPXV protein glycosylation, poly Ser-Arg (poly SR) materials capable of simultaneously enriching both N-glycopeptides and O-glycopeptides were synthesized by surface-initiated reversible addition–fragmentation chain transfer (SI-RAFT) polymerization. The poly SR materials were evaluated using the digest mixture of standard proteins containing bovine fetuin and bovine serum albumin, and the digest of complex biological samples including bovine sperm tail lysate, mouse sperm tail lysate, mouse brain lysate, and human serum. The poly SR materials demonstrated excellent glycopeptide enrichment performance. Subsequently, poly SR materials were applied to comprehensively analyze the N-glycosylation and O-glycosylation of the MPXV structural proteins A29, A35, B6R, and H3L, revealing that these proteins are highly sialylated. To further elucidate the mechanism of MPXV protein infection, the strong specific binding of A29 to heparan sulfate and chondroitin sulfate was determined using glycan microarrays. These findings provide a foundation for understanding the viral infection mechanism and developing vaccines and antiviral drugs.