49P(del)点突变提高中性纤维素内切酶EGV热稳定性的初步研究  被引量:2

Improvement of Cellulase EGV Thermostability by Site-directed Mutagenesis at 49P(del)

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作  者:方芳[1] 曹以诚[1] 陈晓曦[1] 曾炳佳[1] 

机构地区:[1]华南理工大学生物科学与工程学院,广东广州510006

出  处:《现代生物医学进展》2009年第14期2634-2636,共3页Progress in Modern Biomedicine

基  金:国家自然科学基金重大研究计划项目(90412015);教育部中国网格计划生物信息网格平台子项目(B1-137040130);科技部基础学科平台建设生物计算网络平台项目(2005DKA64001)

摘  要:目的:探讨利用点突变方法改善EGV热稳定性的可能性和有效性。方法:对来源于Melanocarpus albomyces endoglucanase的耐热性纤维素酶maEG进行同源建模和序列比较,删除49位脯氨酸49P(del)进行定点突变,并将得到的突变体在毕氏酵母X33中表达,对表达产物进行酶活性和热稳定性检测。结果:突变酶49P(del)在70℃处理120min,热稳定性比EGV提高了21.6%,且突变酶其他性质与野生型酶基本相似。结论:通过对中性纤维素内切酶EGV的定点突变,提高了该酶的热稳定性,并为进一步研究其结构和功能提供了材料。结果同时表明利用生物信息学和分子模拟技术,缩短表面环区对于酶的热稳定性有一定的作用。Objective: To explore the possibility and effects of improving enzyme thermostability by site-directed mutagenesis. Methods: Homology models and sequence alignment were conducted for Melanocarpus albomyces endoglucanase maEG. Then 49P(del) mutation was introduced into wide type EGV by site-directed mutagenesis. Both EGV and the mutant 49P (del) were expressed in Pichia pastoris. Their enzymatic properties were determined. Results: The result revealed that the thermostability of49P (del) was 34.5% higher than that of EGV at 70℃ for 180 min. The optimum temperature of 49P(del ) was increased by 10℃ in mutant enzymes than that in natural phytase. Additionally, the other enzymatic properties of mutant were similar to EGV. Conclusions: The mutant 49P(del) is a good materials for further research on structure and function of Cellulase EGV.

关 键 词:中性纤维素内切酶 49P(del) 定点突变 热稳定性 

分 类 号:Q55[生物学—生物化学] Q78

 

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