Protein-carbohydrate interactions:: A combined theoretical and NMR experimental approach on carbohydrate-aromatic interactions and on pyranose ring distortion

Carbohydrate recognition by lectins and enzymes requires the consideration of a variety of structural and conformational details. The relevance of sugar-aromatic interactions for molecular recognition of carbohydrates by lectins has been studied by a combined protocol using NMR and theoretical calculations. In addition, and in relation to saccharide recognition by glycosidase enzymes, we also present experimental and theoretical evidences on the importance of the chemical nature of the sugar or glycomimetic; to suffer ring distortion. Two different systems (lectin and glycosidase) have been evaluated. As lectin system to test the importance of sugar-aromatic interactions, a chitin binding domain (hevein) has been employed. For the analysis of pyranoid ring distortion, the interaction of E. coli beta-galactosidase with lactose and glycomimetics thereof has been explored. For the theoretical studies, simple models of both the sugar and protein systems have been studied. (c) 2006 American Chemical Society