Structural Basis of Outstanding Multivalent Effects in Jack bean α-Mannosidase Inhibition.

Multivalent design of glycosidase inhibitors is a promising strategy for the treatment of diseases involving enzymatic hydrolysis of glycosidic bonds in carbohydrates. An essential prerequisite for successful applications is the atomic-level understanding of how outstanding binding enhancement occurs with multivalent inhibitors. Herein we report the first high-resolution crystal structures of the Jack bean alpha-mannosidase (JB alpha-man) in apo and inhibited states. The three-dimensional structure of JB alpha-man in complex with the multimeric cyclopeptoid-based inhibitor displaying the largest binding enhancements reported so far provides decisive insight into the molecular mechanisms underlying multivalent effects in glycosidase inhibition.