Identification of activity related amino acid mutations of a GH9 termite cellulase
Identification of activity related amino acid mutations of a GH9 termite cellulase
复制标题
GH9 白蚁纤维素酶活性相关氨基酸突变的鉴定
DOI：
10.1016/j.biortech.2010.03.045
复制
发表时间：
2010-08-01
影响因子：
11.4
通讯作者：
Watanabe, Hirofumi
中科院分区：
文献类型：
--
作者：
Ni, Jinfeng;Takehara, Motomi;Watanabe, Hirofumi
对白蚁Reticulitermes speratus EG（RsEG）的内切β-1，4-葡聚糖酶（EG）基因进行了定点突变，以更好地了解某些氨基酸残基在酶活性中的作用。三个突变体G91 A、Y 97 W和K429 A对羧甲基纤维素酶的活性高于野生型。突变具有协同效应，因为每个单突变体表现出野生型活性的约3-4倍，但双突变体和三突变体的相应活性为7-13倍。突变体G147 R完全丧失酶活性，表明G147在维持酶活性方面起重要作用。Asp 53，Asp 56和Glu 411在酶催化中的预测作用被实验证实，因为所产生的突变体失去了酶活性。本研究首次报道了白蚁EG的氨基酸残基与酶活性的关系，为白蚁纤维素酶的工业化应用提供了依据。(C)2010爱思唯尔有限公司保留所有权利。
Site-directed mutagenesis of the endo-beta-1,4-glucanase (EG) gene from the termite Reticulitermes speratus EG (RsEG) was performed to gain a better understanding of the role of certain amino acid residues in the activity of the enzyme. Three mutants, G91A, Y97W and K429A had higher activities towards carboxymethyl cellulose than the wild type. The mutations had synergistic effects since each single mutant exhibited about 3-4-fold of wild type activity, but the corresponding activities for double and triple mutants were 7-13-fold. Mutant G147R lost the enzymatic activity completely, suggesting G147 plays a significant role in maintaining enzyme activity. The predicted roles of Asp53, Asp56 and Glu411 in enzymatic catalysis were experimentally verified since the resultant mutants lost the enzyme activities. This study presents the first report on the relationship between amino acid residues and enzyme activity of termite EG, and the information will potentially be useful for industrial application of termite-origin cellulase. (C) 2010 Elsevier Ltd. All rights reserved.