A bacterial sulfoglycosidase highlights mucin O-glycan breakdown in the gut ecosystem
A bacterial sulfoglycosidase highlights mucin O-glycan breakdown in the gut ecosystem
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DOI：
10.1038/s41589-023-01272-y
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发表时间：
2023-03-02
影响因子：
14.8
通讯作者：
Katayama, Takane
中科院分区：
文献类型：
--
作者：
Katoh, Toshihiko;Yamada, Chihaya;Katayama, Takane
溶粘菌通过降解粘蛋白o -聚糖的能力调节宿主-微生物共生和生态失调。然而，细菌酶如何以及在多大程度上参与分解过程仍然知之甚少。本文研究了两歧双歧杆菌中的一个糖苷水解酶家族20 -巯基糖苷酶（BbhII），该酶能从硫酸化粘蛋白中释放n -乙酰氨基-6-硫酸酯。糖组学分析表明，除了磺化酶外，磺化糖苷酶还参与了黏液o -聚糖在体内的分解，并且释放的n -乙酰氨基-6-硫酸盐可能影响肠道微生物代谢，这两者也得到了宏基因组数据挖掘分析的支持。BbhII的酶学和结构分析揭示了其特异性的结构，以及glcnac - 6s特异性碳水化合物结合模块（CBM） 32的存在，该模块具有独特的糖识别模式，两歧杆菌利用该模式降解粘蛋白o -聚糖。对突出的溶粘菌基因组的比较分析也突出了两歧双歧杆菌使用的依赖于cbm的o -聚糖分解策略。
Mucinolytic bacteria modulate host-microbiota symbiosis and dysbiosis through their ability to degrade mucin O-glycans. However, how and to what extent bacterial enzymes are involved in the breakdown process remains poorly understood. Here we focus on a glycoside hydrolase family 20 sulfoglycosidase (BbhII) from Bifidobacterium bifidum, which releases N-acetylglucosamine-6-sulfate from sulfated mucins. Glycomic analysis showed that, in addition to sulfatases, sulfoglycosidases are involved in mucin O-glycan breakdown in vivo and that the released N-acetylglucosamine-6-sulfate potentially affects gut microbial metabolism, both of which were also supported by a metagenomic data mining analysis. Enzymatic and structural analysis of BbhII reveals the architecture underlying its specificity and the presence of a GlcNAc-6S-specific carbohydrate-binding module (CBM) 32 with a distinct sugar recognition mode that B. bifidum takes advantage of to degrade mucin O-glycans. Comparative analysis of the genomes of prominent mucinolytic bacteria also highlights a CBM-dependent O-glycan breakdown strategy used by B. bifidum.