Multivalent Galacto-trehaloses: Design, Synthesis, and Biological Evaluation under the Concept of Carbohydrate Modules

Galacto-trehalose (GT) is a novel class of 1,1'-linked nonreducing disaccharide having an alpha-galactoside epitope. In this study, a pair of alpha,alpha- and alpha,beta-GT isomers were prepared in one pot with our alpha-glycosylation method, converted into vinyl monomers and then subjected to radical copolymerization with a second sugar (4-acrylamidophemyl beta-Glc or beta-GlcNAc) in the presence of acrylamide. The derived glycopolymers were assayed with alpha-galactoside-specific proteins (BSI-B-4 lectin and Shiga toxin-1) to show the results that both alpha,alpha- and alpha,beta-isomers are recognized by these carbohydrate-binding proteins more strongly in forms of the GT polymers. Moreover, the glycopolymer carrying both alpha,alpha-GT and beta-GlcNAc along the polymer chain showed an integrated detoxifying activity to the E. coli toxin as the result of a "module effect" of the second sugar.