NMR analysis of the trisaccharide 2′-fucosyllactose by heteronuclear trans-glycosidic coupling constants and molecular simulations

H-1, C-13 NMR coupling constants across the glycosidic linkages were measured for the trisaccharide alpha -L-Fucp-(1 -->2)-beta -D-Galp-(1 -->4)-D-Glcp from human milk and its reduced analogue alpha -L-Fucp-(1 -->2)-beta -D-Galp-(1 -->4)-D-Glucitol employing one-dimensional multiple-site 13C excitation experiments. Hadamard spectroscopy and pulsed field gradients were also used with or without band-selective H-1 decoupling during the acquisition period. The experimental scalar coupling constants were compared to those calculated from Langevin dynamics simulations employing different molecular mechanics force fields. An analysis of (3)J(C,H) values determined with this NMR technique on di- and trisaccharides is also performed. Copyright (C) 2001 John Wiley & Sons, Ltd.