Synthesis of artificial glycoconjugate polymers starting from enzymatically synthesized oligosaccharides and their interactions with lectins.

Styrene derivatives substituted with N-linked beta-anomeric oligosaccharides were synthesized via a simple two-step procedure starting from three enzymatically prepared oligosaccharides: N-acetyllactosamine (Galbeta1-4GlcNAc), N-acetylisolactosamine (Galbeta1-6GlcNAc), and 4'-galactosyllactose (Galbeta1-4Galbeta1-4Glc). Their homo- and copolymerization with acrylamide using 2,2'-azobisisobutyronitrile as an initiator in dimethyl sulfoxide at 60 degreesC gave the corresponding glycopolymers. Binding between glycopolymers and lectins was investigated by means of hemagglutination inhibition experiments. The inhibition of RCA120 lectin-induced hemagglutination by N-acetyllactosamine-carrying homopolymer was about 10(3) times stronger than that of the oligosaccharide itself. The enhanced binding capacity with lectins can be explained in terms of a multivalent or cluster effect along the polymeric chain. In some combinations between lectins and polymers, the copolymers inhibited hemagglutination more strongly than the homopolymers did. N-Acetyllactosamine-carrying glycopolymer showed about 3 x 10(3) times weaker inhibition of DSA lectin-induced hemagglutination than the different type of N-acetyllactosamine-carrying glycopolymer which has an O-linked beta-anomeric phenyl aglycon of each repeating unit along a polyacrylamide backbone.