生孢噬纤维菌纤维素酶关键氨基酸饱和突变及性质  

Saturation mutation of key amino acids of cellulase from Sporocytophaga myxococcoides and properties of the mutants

作　　者：王辛 方程 盛钧美 陈晓艺[1] WANG Xin;FANG Cheng;SHENG Junmei;CHEN Xiaoyi(School of Biological Engineering,Dalian Polytechnic University,Dalian 116034,China)

机构地区：[1]大连工业大学生物工程学院,辽宁大连116034

出　　处：《大连工业大学学报》2022年第4期246-250,共5页Journal of Dalian Polytechnic University

基　　金：辽宁省自然科学基金项目(2020-MS-276).

摘　　要：Sm_2974是来源于生孢噬纤维菌(Sporocytophaga myxococcoides)的一个双功能纤维素酶,具有较高的催化效率。以Sm_2974为模板,将第205位色氨酸残基进行饱和突变后,所有突变体的CMC酶活和pNPC酶活均有不同程度的降低,而色氨酸向酪氨酸的突变使Sm_2974的pNPC酶活完全丧失。突变为天冬氨酸使Sm_2974对滤纸纤维素的水解能力增加,而突变为苏氨酸和谷氨酰胺则使Sm_2974与滤纸底物的结合能力降低,进而影响了酶催化效率。结果表明,第205位色氨酸残基对Sm_2974的底物结合能力及纤维素水解能力均有重要影响,可能是酶活性中心的关键氨基酸残基。Sm_2974 is a bifunctional cellulase with high catalytic efficiency derived from Sporocytophaga myxococcoides.The tryptophan residue at W205 was subjected to saturation mutation using Sm_2974 as a template.The CMC and p NPC enzyme activities of all mutants were decreased to varying degrees,while the mutation of tryptophan to tyrosine completely lost the p NPC enzyme activity of Sm_2974.Mutation to aspartic acid increased the hydrolysis ability of Sm_2974 to filter paper,while mutations to threonine and glutamine reduced the binding ability of Sm_2974 to the substrate,and therefore affected the catalytic efficiency of enzyme.The results showed that W205 residue of Sm_2974 had an effect on the ability of both substrate binding and cellulose hydrolysis,and may be a key amino acid in the active center of the enzyme.

关 键 词：生孢噬纤维菌 纤维素酶 饱和突变 

分 类 号：Q816[生物学—生物工程]