Crystal structure of the Enterococcus faecalis α-N-acetylgalactosaminidase, a member of the glycoside hydrolase family 31
Crystal structure of the Enterococcus faecalis α-N-acetylgalactosaminidase, a member of the glycoside hydrolase family 31
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DOI：
10.1002/1873-3468.13804
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发表时间：
2020-05-22
期刊：
影响因子：
3.5
通讯作者：
Park, Enoch Y.
中科院分区：
文献类型：
--
作者：
Miyazaki, Takatsugu;Park, Enoch Y.
糖苷水解酶催化碳水化合物中糖苷键的水解。糖苷水解酶家族 31 (GH31) 包含 α-葡萄糖苷酶、α-木糖苷酶、α-半乳糖苷酶和 α-转糖基酶。最近的工作扩大了 GH31 酶底物特异性的多样性，并且已在人类肠道细菌中鉴定出属于 GH31 的 α-N-乙酰氨基半乳糖苷酶（α GalNAcases）。在这里，我们确定了来自人类肠道细菌粪肠球菌的 GH31 α GalNAcase 的截短形式的第一个晶体结构。该酶与其他报道的 GH31 酶具有相似的折叠，并具有额外的 3 型纤连蛋白样结构域。此外，与 N-乙酰半乳糖胺复合的结构揭示了活性位点残基（包括其催化亲核试剂）的构象发生变化以识别配体。我们的结构分析提供了对 GH31 α GalNAcases 的底物识别和催化机制的深入了解。
Glycoside hydrolases catalyze the hydrolysis of glycosidic linkages in carbohydrates. The glycoside hydrolase family 31 (GH31) contains alpha-glucosidase, alpha-xylosidase, alpha-galactosidase, and alpha-transglycosylase. Recent work has expanded the diversity of substrate specificity of GH31 enzymes, and alpha-N-acetylgalactosaminidases (alpha GalNAcases) belonging to GH31 have been identified in human gut bacteria. Here, we determined the first crystal structure of a truncated form of GH31 alpha GalNAcase from the human gut bacterium Enterococcus faecalis. The enzyme has a similar fold to other reported GH31 enzymes and an additional fibronectin type 3-like domain. Additionally, the structure in complex with N-acetylgalactosamine reveals that conformations of the active site residues, including its catalytic nucleophile, change to recognize the ligand. Our structural analysis provides insight into the substrate recognition and catalytic mechanism of GH31 alpha GalNAcases.