Enzymatic glycosylation of polyphenols is a tool to improve their physicochemical properties and bioavailability. On the other hand, glycosidic enzymes can be inhibited by phenolic compounds. In this work, we studied the specificity of various phenolics (hydroquinone, hydroxytyrosol, epigallocatechin gallate, catechol and p-nitrophenol) as fructosyl acceptors or inhibitors of the β-fructofuranosidase from Xanthophyllomyces dendrorhous (pXd-INV). Only hydroquinone and hydroxytyrosol gave rise to the formation of glycosylated products. To disclose the binding mode of each compound and elucidate the molecular features determining its acceptor or inhibitor behaviour, ternary complexes of the inactive mutant pXd-INV-D80A with fructose and the different polyphenols were analyzed by X-ray crystallography. The acceptor capacity of the different polyphenols seems mediated by their ability to make flexible polar links with the protein.
Reference: “Deciphering the molecular specificity of phenolic compounds as inhibitors or glycosyl acceptors of β fructofuranosidase from Xanthophyllomyces dendrorhous”. M. Ramirez-Escudero, N. Miguez, M. Gimeno-Perez, A.O. Ballesteros, M. Fernandez-Lobato, F.J. Plou* and J. Sanz-Aparicio* Scientific Reports 9, 17441 (2019), doi:10.1038/s41598-019-53948-y