NMR study of a LewisX pentasaccharide derivative: solution structure and interaction with cations

The structure and conformation of the synthetic pentasaccharide Gal(β1-4){Fuc(α1-3)}GlcNAc(β1-3)Gal(β1-4)Glc-βOMe of the LewisX family has been determined by NMR spectroscopy in dimethyl sulfoxide and methanol. In these solvents, the binding constants with calcium have been evaluated as 9.5 and 29.6 M−1, respectively. Study of the interaction sites has been achieved through the use of paramagnetic divalent cations and distance triangulation methods. Two regions have been found, the first one in the vicinity of the fucose unit, the second one closer to the lactose part.