Identification and characterization of a sulfoglycosidase from Bifidobacterium bifidum implicated in mucin glycan utilization |
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Authors: | Toshihiko Katoh Takako Maeshibu Kei-ichi Kikkawa Aina Gotoh Yusuke Tomabechi Motoharu Nakamura |
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Institution: | 1. Graduate School of Biostudies, Kyoto University, Kyoto, Japan;2. Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan;3. Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan |
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Abstract: | Human gut symbiont bifidobacteria possess carbohydrate-degrading enzymes that act on the O-linked glycans of intestinal mucins to utilize those carbohydrates as carbon sources. However, our knowledge about mucin type O-glycan degradation by bifidobacteria remains fragmentary, especially regarding how they decompose sulfated glycans, which are abundantly found in mucin sugar-chains. Here, we examined the abilities of several Bifidobacterium strains to degrade a sulfated glycan substrate and identified a 6-sulfo-β-d-N-acetylglucosaminidase, also termed sulfoglycosidase, encoded by bbhII from Bifidobacterium bifidum JCM 7004. A recombinant BbhII protein showed a substrate preference toward 6-sulfated and 3,4-disulfated N-acetylglucosamines over non-sulfated and 3-sulfated N-acetylglucosamines. The purified BbhII directly released 6-sulfated N-acetylglucosamine from porcine gastric mucin and the expression of bbhII was moderately induced in the presence of mucin. This de-capping activity may promote utilization of sulfated glycans of mucin by other bacteria including bifidobacteria, thereby establishing the symbiotic relationship between human and gut microbes. |
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Keywords: | sulfoglycosidase Bifidobacterium bifidum mucin sulfated glycan 6-sulfated N-acetylglucosamine |
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