Glycosidase−Substrate Interactions Analysis by STD-NMR Spectroscopy: Study of α-l-Fucosidase

Saturation transfer difference-nuclear magnetic resonance (STD-NMR) is a recently developed method used to study the interaction between large proteins and small ligands. It has been successfully employed for various interactions including those between oligosaccharides or glycomimetics, and binding proteins such as lectins and antibodies. We have demonstrated that this method can be used to directly study the interaction between glycosidases and their substrates. We chose to study α-l-fucosidases, which, despite their wide distribution among living organisms and their biological significance, have not been studied with regard to their reaction mechanism. We were able for the first time to show direct evidences for the minimum structural requirements for a compound to interact with these enzymes. These findings will be useful for the design of new inhibitors and to optimize the synthetic properties (transglycosylation) of α-l-fucosidases.