摘要
为确定嗜热酸性生淀粉α-淀粉酶Gt-amy中结构域C对其催化性能的影响,本研究采用基于蛋白质分子结构的环化重排方法对Gt-amy的结构域C进行分子改造,获得Gt-amy环化重排突变体,并比较了突变体的生淀粉吸附率、生淀粉降解率、酶比活力以及动力学常数.与Gt-amy相比,生淀粉吸附能力提高的Gt-amy环化重排突变体,其生淀粉降解能力也得到提高;生淀粉吸附能力降低的Gt-amy环化重排突变体,其生淀粉降解能力也降低.即Gt-amy的生淀粉降解能力和生淀粉吸附能力之间存在正相关性.其中,环化重排突变体Gt-amy-S498的生淀粉吸附率由78.86%提高至93.14%,生淀粉降解率由65.80%提高至90.93%.本研究证实环化重排突变可以作为一种工程学手段改变蛋白质的结构与功能,为提高酶类蛋白质的催化性能提供了思路.
In order to determine the effect of domain C of thermoacidiphilic raw starch-degrading α-amylase Gt-amy on its catalytic properties, circulation permutation based on protein molecular structure was used to construct circularly permutated mutants of Gt-amy. The abilities of Gt-amy and the mutants to adsorb onto and hydrolyze raw corn starch were investigated. Moreover, the specific activities and kinetic constants were also measured. Compared with Gt-amy, the mutants with higher raw corn starch-binding capacity had higher raw corn starch degradation capacity, and those with lower raw corn starch binding capacity had lower raw corn starch degradation capacity, i.e, there was a positive correlation between Gt-amy’s capacity to bind to and degrade raw corn starch. The raw corn starch binding and degradation rates of mutant Gt-amy-S498 were 93.14% and 90.93%, respectively, which were higher than those of Gt-amy (78.86% and 65.80%). This study confirms that circulation permutation can be used as an engineering method to change the structure and function of proteins, and provides a new way to improve the catalytic performance of enzymes.
作者
曾静
郭建军
涂熠坤
魏国汶
袁林
ZENG Jing;GUO Jianjun;TU Yikun;WEI Guowen;YUAN Lin(Institute of Microbiology,Jiangxi Academy of Sciences,Nanchang 330096,China;School of Chemistry and Molecular Engineering,Nanjing Tech University,Nanjing 211800,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2019年第20期144-151,共8页
Food Science
基金
国家自然科学基金青年科学基金项目（31501422）
江西省青年科学基金项目（20171BAB214003）
江西省科学院杰出青年项目（2018-JCQN-02）
江西省科学院产学研合作项目(2018-YCXY-02)
关键词
嗜热酸性生淀粉α-淀粉酶
环化重排
生淀粉吸附率
生淀粉降解率
催化性能
thermoacidiphilic raw starch degrading α-amylase
circulation permutation
raw starch binding
raw starchhydrolysis
catalytic performance
