500-MHz 1H-n.m.r. and conformational studies of fucosyloligosaccharides recognised by monoclonal antibodies with specificities related to Le(a), Le(b), and SSEA-1.

500-MHz 1H-n.m.r. spectroscopy has been used to examine several fucosylated oligosaccharides in studies to characterise carbohydrate antigenic determinants recognised by monoclonal antibodies. Reduction of the oligosaccharides to give additional variants for analysis showed that oligosaccharides having an alpha-L-fucosyl group linked to the reducing end residue have markedly different chemical shifts, and in some instances different antigenic activity, compared to their alditols. This information was incorporated into space filling molecular models of the oligosaccharides in order to predict the topography of atoms recognised by the antibody combining sites. These studies are an intermediate stage in the full characterisation of oligosaccharide conformation and molecular recognition by methods which accurately determine torsional angles and through-space internuclear distances.