Chemoenzymatic Synthesis of Highly O‐Glycosylated MUC7 Glycopeptides for Probing Inhibitory Activity against Pseudomonas aeruginosa Biofilm Formation

MUC7, a highly glycosylated protein in saliva and respiratory tract, plays potential roles in facilitating bacterial clearance and preventing microbial invasion. The complexity of glycan structures and multiplicity of glycosylation sites of MUC7 make it very difficult to explore accurate biofunctions against pathogens. Here, we report an efficiently convergent chemoenzymatic approach to firstly synthesize highly O-glycosylated MUC7 glycopeptides with nine glycosylation sites bearing various glycoforms via the combined use of hydrophobic tag-assisted liquid-phase peptide synthesis and enzymatic-catalyzed glycan elongation. Biological evaluations reveal that different glycoforms of synthetic MUC7 glycopeptides mediate unique activities against biofilm formation of Pseudomonas aeruginosa, among which sialylated MUC7 glycopeptide exhibits better inhibitory activity and has the potential to develop antibacterial drugs.