Identification and characterization of a sulfoglycosidase from Bifidobacterium bifidum implicated in mucin glycan utilization
Identification and characterization of a sulfoglycosidase from Bifidobacterium bifidum implicated in mucin glycan utilization
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DOI：
10.1080/09168451.2017.1361810
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发表时间：
2017-01-01
影响因子：
1.6
通讯作者：
Katayama, Takane
中科院分区：
文献类型：
--
作者：
Katoh, Toshihiko;Maeshibu, Takako;Katayama, Takane
人体肠道共生菌双歧杆菌具有碳水化合物降解酶，作用于肠道粘蛋白的O-连接的糖链，以利用这些碳水化合物作为碳源。然而，我们对双歧杆菌降解粘蛋白型O-葡聚糖的了解仍然是零散的，特别是关于它们如何分解硫化多糖，这些多糖丰富地存在于粘蛋白糖链中。在这里，我们检测了几个双歧杆菌菌株降解硫酸多糖底物的能力，并鉴定了一种6-磺基-d-N-乙酰氨基葡萄糖苷酶，也称为磺基糖苷酶，由双歧双歧杆菌JCM 7004的bbhII编码。重组BbhII蛋白对6-硫化和3，4-二硫化N-乙酰氨基葡萄糖的底物选择性高于非硫化和3-硫化的N-乙酰氨基葡萄糖。纯化的BbhII直接从猪胃粘液中释放6-硫酸N-乙酰氨基葡萄糖，并在粘蛋白存在下适度诱导BbhII的表达。这种脱帽活性可能会促进包括双歧杆菌在内的其他细菌对粘蛋白的硫化葡聚糖的利用，从而建立人与肠道微生物之间的共生关系。
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--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.