Characterization of a new α-L-fucosidase isolated from Fusarium proliferatum LE1 that is regioselective to α-(1 → 4)-L-fucosidic linkage in the hydrolysis of α-L-fucobiosides

Here, we report the biochemical characterization of a novel alpha-L-fucosidase with broad substrate specificity (FpFucA) isolated from the mycelial fungus Fusarium proliferatum LE1. Highly purified alpha-L-fucosidase was obtained from several chromatographic steps after growth in the presence of L-fucose. The purified alpha-L-fucosidase appeared to be a monomeric protein of 67 +/- 1 kDa that was able to hydrolyze the synthetic substrate p-nitrophenyl alpha-L-fucopyranoside (pNPFuc), with K-m = 1.1 +/- 0.1 mM and k(cat) = 39.8 +/- 1.8 s(-1). L-fucose, 1-deoxyfuconojirimycin and tris(hydroxymethyl)aminomethane inhibited pNPFuc hydrolysis, with inhibition constants of 0.2 +/- 0.05 mM, 7.1 +/- 0.05 nM, and 12.2 +/- 0.1 mM, respectively. We assumed that the enzyme belongs to subfamily A of the GH29 family (CAZy database) based on its ability to hydrolyze practically all fucose-containing oligosaccharides used in the study and the phylogenetic analysis. We found that this enzyme was a unique alpha-L-fucosidase that preferentially hydrolyzes the alpha-(1 -> 4)-L-fucosidic linkage present in alpha-L-fucobiosides with different types of linkages. As a retaining glycosidase, FpFucA is capable of catalyzing the transglycosylation reaction with alcohols (methanol, ethanol, and 1-propanol) and pNP-containing monosaccharides as acceptors. These features make the enzyme an important tool that can be used in the various modifications of valuable fucose-containing compounds. (C) 2016 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.