Electrochemically assembled oligovalent glycomimetics as potent inhibitors of bacterial sialidases

Gut microbiota dysbiosis is a hallmark of Crohn’s disease (CD), with increased availability of host-derived nutrients contributing to the expansion of pathogenic bacteria such as adherentinvasive Escherichia coli (AIEC). Microbial sialidases play a key role in mucin degradation by releasing N-acetylneuraminic acid, thereby promoting bacterial nutrient scavenging and colonization. Here, we report a new strategy for targeting intestinal sialidase activity through the development of multivalent glycomimetic inhibitors generated by electrochemically promoted bioconjugation (eY-click). S-linked Neu5Ac and transition-state analogue Neu5Ac2en derivatives were equipped with phenylurazole or N-methylluminol electroactive handles and efficiently conjugated onto tyrosine-containing peptide scaffolds under mild aqueous conditions. This approach enabled the formation of oligovalent sialidase inhibitors with varied ligand density. The resulting compounds displayed potent inhibitory activity against gut microbiota sialidases from Bacteroides thetaiotaomicron and Bacteroides vulgatus, demonstrating strong multivalent enhancement despite their relatively low valency compared with previously reported polymeric inhibitors. Notably, Neu5Ac2en-based oligovalent inhibitor effectively suppressed AIEC LF82 growth driven by sialidase-mediated Neu5Ac release from mucin, outperforming a previously described high-valency polymeric inhibitor. Beyond sialidase inhibition, this work establishes eY-click as a versatile method for constructing multivalent biomolecular inhibitors and provides a new avenue for targeting microbial carbohydrate metabolism in inflammatory bowel disease.