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

Abstract

<p class="first" id="d3106731e216"> <i>Bifidobacterium longum</i> subsp. <i>infantis</i> 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 <i>et al.</i>: <i>Appl. Environ. Microbiol.,</i> 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 <i>N</i>-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- <i>N</i>-acetylglucosaminidase. We demonstrated that Blon_0426 can de-fucosylate Fucα1-6GlcNAc-IgG prepared from Rituximab using Endo-CoM from <i>Cordyceps militaris</i>. To generate homogenous non-fucosylated <i>N</i>-glycan-containing IgG with high antibody-dependent 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 <i>Mucor hiemalis</i>. Collectively, our results strongly suggest that Blon_0426 and Blon_0248 are useful for glycoprotein glycan remodeling. </p>