Impact of Glycans Modulating Human Cytomegalovirus Glycoprotein B on Broad-Spectrum Neutralizing Human Antibody...

Viral fusion glycoproteins are extensively glycosylated, a feature that is critical for viral entry and antibody responses. However, the structural complexity of N-glycans and experimental limitations have hindered mechanistic studies of glycan-glycoprotein interactions and the impact of glycosylation on host immunity. Human cytomegalovirus (HCMV) relies on glycoprotein B (gB) to mediate viral membrane fusion and cell entry. Like other viral fusion proteins, gB employs N-glycans to facilitate viral entry while evading host immune responses. Here, we constructed models of the glycosylated gB trimer and its complexes with different neutralizing antibodies and performed large-scale molecular dynamics simulations to investigate how N-glycans influence protein dynamics and antibody recognition. Our results show that N-glycans stabilize the gB conformation through interactions with domains DI and DII. Moreover, glycans at N281, N286, and N302 unevenly shield the epitope of the neutralizing antibody 1G2, thereby modulating its immune recognition. Glycosylation also moderately reduces the interaction between gB and antibody 1B03, while key residues His182, Arg311, and Asn313 continue to contribute to the binding interface. This study enhances the mechanistic understanding of how N-glycans regulate viral fusion glycoproteins and provides a molecular foundation for the development of broadly neutralizing antibodies.