Substrate recognition of glucosidase II in ER and its related enzymes

该项目的目的是阐明主要分布在生物体中的α-葡萄糖苷酶的分子进化。安在内质网中水解α-1，3-糖苷键的葡萄糖苷酶对α-1，4-糖苷键也具有特异性。结构研究的一个。葡萄糖苷酶的结果表明，覆盖活性口袋的环结构参与底物识别。色氨酸残留在酵母的活性口袋里。葡萄糖苷酶对底物专一性有重要作用。小说。葡萄糖苷酶是从细菌中发现的一种以α-1，3-糖苷键为优势的糖苷酶。一种祖先酶最初似乎具有α-1，3特异性，其衍生物在分子进化过程中获得了各种特异性。此外，具有新功能的蛋白质似乎仍保留在相关家族中

The purpose of this project was to clarify molecular evolution ofα-glucosidases distributed largely in organisms. An.-glucosidase, which hydrolyzesα-1, 3-glucosidic linkage in endoplasmic reticulum, also showed specificity forα-1, 4-glucosidic linkage. Structural studies of an.-glucosidase indicated that the loop structure, which covers the active pocket, was involved in substrate recognition. Trp residue in the active pocket of an yeast.-glucosidase had important role for substrate specificity. Novel.-glucosidase, which preferredα-1, 3-glucosidic linkage, was discovered from bacteria. It seems that an ancestor enzyme originally hadα-1, 3 specificity and its derivatives have acquired various specificity during the molecular evolution. Moreover, it appears that protein with a new function remained in the related family