Synthesis and molecular recognition of carbohydrate-centered multivalent glycoclusters by a plant lectin RCA120.

Water soluble and lectin-recognizable carbohydrate-centered glycoclusters were prepared efficiently by the Huisgen 1,3-cycloaddition reaction of methyl-2,3,4,6-tetra-O-propargyl beta-D-galactopyranoside with 2-azidoethyl glycosides of lactose and N-acetyllactosamine. Their binding by a plant lectin RCA120 was examined by capillary affinity electrophoresis using fluorescence-labeled asialoglycans from human alpha1-acid glycoprotein. The glycoclusters showed 400-fold stronger inhibitory effect than free lactose, manifesting strong multivalency effect.