WbgL: a novel bacterial α1,2-fucosyltransferase for the synthesis of 2'-fucosyllactose.

Fucosyltransferases (FucTs) are essential tools for the synthesis of fucosylated glycoconjugates. Multistep enzyme catalysis of fucosylated glycans is not limited as long as isolated and well-characterized FucTs are available. The present paper introduces a novel bacterial α1,2-FucT of the glycosyltransferase family 11 encoded by the gene wbgL in the E. coli O126 genome, which only displays 25-30% homology to previously published α1,2-FucTs. A tailor made cloning and expression strategy allowed the successful production of active soluble enzyme in the cytoplasm of E. coli BL21(DE3) and E. coli JM109(DE3), respectively. The lack of a DxD motif and its high activity without divalent metal ions suggests that WbgL belongs to the GT-B fold superfamily. Substrate screening revealed the highest activity for β4-linked galactoside acceptor substrates, such as lactose and lactulose, making WbgL unique among other characterized α1,2-FucTs. Based on its excellent kinetic efficiency for lactose, we present here a sequential reaction strategy for the synthesis of α1,2-fucosyllactose in one pot including the synthesis of the donor substrate 3,3'-Diaminobenzidine (GDP)-β-l-fucose by the bifunctional l-fucokinase/GDP-β-l-Fuc pyrophosphorylase of Bacteroides fragilis 9343.