Synthesis of Artificial Glycoconjugate Polymers Starting from Enzymatically Synthesized Oligosaccharides and Their Interactions with Lectins

Abstract

Styrene derivatives substituted with N-linked β-anomeric oligosaccharides were synthesized via a simple two-step procedure starting from three enzymatically prepared oligosaccharides: N-acetyllactosamine (Ga1β1–4GlcNAc), N-acetylisolactosamine (Galβ1–6GlcNAc), and 4'-galactosyllactose (Gal β1 4Gal β1–4Glc). Their homo- and copolymerization with acrylamide using 2, 2'-azobisisobutyronitrile as an initiator in dimethyl sulfoxide at 60°C gave the corresponding glycopolymers. Binding between glycopolymers and lectins was investigated by means of hemagglutination inhibition experiments. The inhibition of RCA.20 lectin-induced hemagglutination by N-acetyllactosamine-carrying homopolymer was about 10³ 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 3×10³ times weaker inhibition of DSA lectininduced hemagglutination than the different type of N-acetyllactosamine-carrying glycopolymer which has an O-linked β-anomeric phenyl aglycon of each repeating unit along a polyacrylamide backbone.