N-Acetyllactosaminooligosaccharides that contain the β- d-Glc pNAc-(1→6)- d-Gal or β- d-Glc pNAc-(1→6)- d-GalNAc sequences reveal reduction-sensitive affinites for wheat germ agglutinin

Abstract

Affinity chromatography of unreduced oligosaccharides on a small column of immobilized wheat germ agglutinin (WGA) revealed high-binding affinites for several radiolabeled molecules containing at the reducing end either β- d-Glc pNAc-((1→6)- d-Glc p-(1→6)-β- d-Gal p-(1→4)- d-GlcNAc, β- d-Glc pNAc-(1→6)- β- d-Gal p(1→4) dGlc, d-Glc pNac-(→3)-[β- d-Glc pNAc-(1→6)- d-GalNAc, or β- d-Gal p-(→3)-[β- d-Glc pNAc-(1→6)- d-GalNAc sequences. Reduction changed the binding affinites remarkably: The sequences carrying a d-galactose or 2-acetamido-2-deoxy- d-galactose residue at the reducing end lost most of their affinities, but the sequences containing a d-glucose or 2-acetamido-2-deoxy- d-glucose residue at the reducing end gained additional affinity upon reduction. These findings emphasize the role of the unreduced, 6-o-substituted d-galactose and 2-acetamido-2-deoxy- d-galactose residues for the binding of saccharides to WGA, which has been recognized previously as a lectin specific for oligosaccharides containing a 2-acetamido-2-deoxy- d-glucose or sialic acid unit. The results suggested also that WGA-agarose chromatography of alditols may become a valuable method for the fractionation of oligo- N-acetyllactosaminoglycans and related saccharides.