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 measur ed for the trisaccharide alpha -L-Fucp-(1 -->2)-beta -D-Galp-(1 -->4)-D-Glc p from human milk and its reduced analogue alpha -L-Fucp-(1 -->2)-beta -D-G alp-(1 -->4)-D-Glucitol employing one-dimensional multiple-site 13C excitat ion 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 c alculated from Langevin dynamics simulations employing different molecular mechanics force fields. An analysis of (3)J(C,H) values determined with thi s NMR technique on di- and trisaccharides is also performed. Copyright (C) 2001 John Wiley & Sons, Ltd.