1,6-α-L-Fucosidases from Bifidobacterium longum subsp. infantis ATCC 15697 Involved in the Degradation of Core-fucosylated N-Glycan

Bifidobacterium longum subsp.infantis ATCC 15697 possesses five α-L-fucosidases, which have been previously characterized toward fucosylated human milk oligosaccharides containing α1,2/3/4-linked fucose [Sela et al.: Appl.Environ.Microbiol., 78, 795-803 (2012)].In this study, two glycoside hydrolase family 29 α-L-fucosidases out of five (Blon_0426 and Blon_0248) were found to be 1,6-α-L-fucosidases acting on core α1,6-fucose on the N-glycan of glycoproteins.These enzymes readily hydrolyzed p-nitrophenyl-α-L-fucoside and Fucα1-6GlcNAc, but hardly hydrolyzed Fucα1-6(GlcNAcβ1-4)GlcNAc, suggesting that they de-fucosylate Fucα1-6GlcNAcβ1-Asn-peptides/ proteins generated by the action of endo-β-N-acetylglucosaminidase.We demonstrated that Blon_0426 can de-fucosylate Fucα1-6GlcNAc-IgG prepared from Rituximab using Endo-CoM from Cordyceps militaris.To generate homogenous non-fucosylated N-glycan-containing IgG with high antibodydependent cellular cytotoxicity (ADCC) activity, the resulting GlcNAc-IgG has a potential to be a good acceptor substrate for the glycosynthase mutant of Endo-M from Mucor hiemalis.Collectively, our results strongly suggest that Blon_0426 and Blon_0248 are useful for glycoprotein glycan remodeling.