Domain Structure and Function of α-1,3-Glucanase from Bacillus circulans KA-304, an Enzyme Essential for Degrading Basidiomycete Cell Walls
Domain Structure and Function of α-1,3-Glucanase from Bacillus circulans KA-304, an Enzyme Essential for Degrading Basidiomycete Cell Walls
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DOI：
10.1271/bbb.120900
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
Wasana Suyotha;Shigekazu Yano;K. Takagi;Nopakarn Rattanakit-Chandet;T. Tachiki;M. Wakayama
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文献类型：
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作者：
Wasana Suyotha;Shigekazu Yano;K. Takagi;Nopakarn Rattanakit-Chandet;T. Tachiki;M. Wakayama
环状芽孢杆菌KA-304 α-1，3-葡聚糖酶（Agl-KA）包括N-末端盘状结构域（DS 1）、碳水化合物结合模块家族6（CB 6）、苏氨酸和脯氨酸重复序列（TP）、第二盘状结构域（DS 2）、未表征的保守结构域（UCD）和C-末端催化结构域。缺失DS 1、CB 6和DS 2的结构域缺失酶表现出比野生型Agl-KA更低的α-1，3-葡聚糖水解和结合活性。用荧光蛋白融合蛋白进行的α-1，3-葡聚糖结合试验表明，DS 1、CB 6和DS 2与α-1，3-葡聚糖和真菌细胞壁结合，并且结合效率通过它们的联合作用而增加。相反，UCD没有表现出任何α-1，3-葡聚糖结合活性。在裂褶菌菌丝体中的原生质体形成的急剧下降，观察到只有一个DS 1缺失。缺失DS 1、CB 6和DS 2的Agl-KA不产生原生质体。这些结果表明，DS 1，CB 6和DS 2的组合作用有助于增加细胞壁结合，并且对于有效的Agl-KA细胞壁降解是必不可少的。
Bacillus circulans KA-304 α-1,3-glucanase (Agl-KA) includes an N-terminal discoidin domain (DS1), a carbohydrate binding module family 6 (CB6), threonine and proline repeats (TPs), a second discoidin domain (DS2), an uncharacterized conserved domain (UCD), and a C-terminal catalytic domain. Domain deletion enzymes lacking DS1, CB6, and DS2 exhibited lower α-1,3-glucan-hydrolyzing and -binding activities than the wild type, Agl-KA. An α-1,3-glucan binding assay with fluorescent protein fusion proteins indicated that DS1, CB6, and DS2 bound to α-1,3-glucan and fungal cell walls, and that binding efficiency was increased by their combined action. In contrast, UCD did not exhibit any α-1,3-glucan-binding activity. A dramatic decrease in protoplast formation in the Schizophyllum commune mycelium was observed given only a DS1 deletion. An Agl-KA with deletion DS1, CB6, and DS2 produced no protoplasts. These results indicate that the combined actions of DS1, CB6, and DS2 contributed to increased cell-wall binding and were indispensable for efficient Agl-KA cell-wall degradation.