Conformational differences between O- and C-glycosides: the alpha-O-man-(1-->1)-beta-Gal/alpha-C-Man-(1-->1)-beta-Gal case--a decisive demonstration of the importance of the exo-anomeric effect on the conformation of glycosides.
The conformational behavior of alpha-O-Man-(1-->1)-beta-Gal (1) and its C-analogue (2) has been studied using J/NOE NMR data, molecular mechanics, molecular dynamics, and ab initio calculations. The population distribution around the glycosidic linkages of 1 and 2 is rather different, especially for the alpha-Man linkage. A lower limit for the exo-anomeric effect in water has been experimentally determined.
Asensio
J L
JL
Departamento de Química Orgánica Biológica, CSIC, Madrid, Spain.
Cañada
F J
FJ
Cheng
X
X
Khan
N
N
Mootoo
D R
DR
Jiménez-Barbero
J
J
D002236:Carbohydrate Conformation; D004187:Disaccharides / Q000737:chemistry; D005690:Galactose / Q000737:chemistry; D006027:Glycosides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000737:chemistry; D008958:Models, Molecular
D004187:Disaccharides; D006027:Glycosides; D008358:Mannose; D005690:Galactose