Synthesis of mucin type core 3 and core 5 structures and their interaction analysis with sugar chips

For the functional analysis of mucin related glycan, we synthesized core 3 and 5 structures of mucin type O-glycan and investigated their binding interaction with lectins using sugar chip technology. The construction of Tn antigen moiety containing α-N-acetylgalactosamine residue was achieved by α-selective glycosylation of 2-azido-6-tert-butyldiphenylsilyl-3,4-di-O-chloroacetyl-2-deoxy-galctopyranosyl imidate and glucose moiety, which acts as a hydrophilic spacer when immobilized on a gold-coated sensor chip. Core 3 and core 5 structures were synthesized by the glycosylation of appropriate N-acetylglucosamine and N-galactosamine donors, respectively, and were converted into sugar-chain ligand conjugates according to the method reported. The interaction analysis of lectins with sugar chips coated with ligand conjugates was performed with a surface plasmon resonance (SPR) biosensor. The specific interaction was observed between the core 3 structure and Jacalin (JAC) and kinetic parameters were estimated as ka = 1.5 × 104, kd = 5.8 × 10−3, and KD = 3.8 × 10−7.