A triazatruxene-based glycocluster as a fluorescent sensor for concanavalin A.

A new triazatruxene-based fluorescent glycocluster has been designed, synthesized, and fully characterized by NMR spectroscopy and mass spectrometry. Furthermore, its specific and selective binding properties with concanavalinA (ConA) have been investigated by fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and turbidity assay. The obtained results showed that the multivalent mannose-modified triazatruxene exhibited specific binding with ConA, but no binding to peanut agglutinin (PNA) lectin or bovine serum albumin (BSA), corresponding to a two-orders-of-magnitude higher affinity than that of monovalent mannose ligands. Most interestingly, a fluorescence enhancement of the triazatruxene-based glycocluster was observed upon binding with ConA because of hydrophobic interactions involving sites close to the triazatruxene moiety. Furthermore, the inhibitory ability of the triazatruxene-based glycocluster against ORN178- induced haemagglutination has been investigated by haemagglutination inhibition assay. The results indicated selective binding with ORN178.