An inverting β‐1,2‐mannosidase belonging to glycoside hydrolase family 130 from Dyadobacter fermentans
An inverting β‐1,2‐mannosidase belonging to glycoside hydrolase family 130 from Dyadobacter fermentans
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DOI：
10.1016/j.febslet.2015.10.008
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发表时间：
2015-11
期刊：
影响因子：
3.5
通讯作者：
T. Nihira;K. Chiku;E. Suzuki;M. Nishimoto;S. Fushinobu;M. Kitaoka;K. Ohtsubo;Hiroyuki Nakai
中科院分区：
文献类型：
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作者：
T. Nihira;K. Chiku;E. Suzuki;M. Nishimoto;S. Fushinobu;M. Kitaoka;K. Ohtsubo;Hiroyuki Nakai
糖苷水解酶家族(GH)由催化β-d-甘露糖苷可逆磷酸化的转化磷酸化酶组成。在这里，我们报告了一个糖苷水解酶，它是GH130的一个新成员。DFER_3176不能利用α-d-甘露糖1-磷酸合成α-d-甘露糖，但能从β-1，2-甘露低聚糖中释放β-d-甘露糖，构型反转，表明DFER_3176是一种DFER-1，2-甘露糖苷酶。突变分析表明，两个谷氨酸残基对β-1，2-甘露三糖的水解至关重要。这两个残基在GH130磷酸化酶中不保守，预计在β-d-甘露糖键的水解中有助于水分子的亲核攻击。
The glycoside hydrolase family (GH) 130 is composed of inverting phosphorylases that catalyze reversible phosphorolysis of β-d-mannosides. Here we report a glycoside hydrolase as a new member of GH130. Dfer_3176 fromDyadobacter fermentansshowed no synthetic activity using α-d-mannose 1-phosphate but it released α-d-mannose from β-1,2-mannooligosaccharides with an inversion of the anomeric configuration, indicating that Dfer_3176 is a β-1,2-mannosidase. Mutational analysis indicated that two glutamic acid residues are critical for the hydrolysis of β-1,2-mannotriose. The two residues are not conserved among GH130 phosphorylases and are predicted to assist the nucleophilic attack of a water molecule in the hydrolysis of the β-d-mannosidic bond.