摘要
通过对来源于海洋芽孢杆菌Y112的环糊精葡糖基转移酶进行同源建模及氨基酸序列比对,发现N末端81位精氨酸可能影响环糊精产物特异性。本研究通过定点突变将第81位点处的精氨酸突变为苏氨酸,降低了α-环糊精的生成量,将β-环糊精的比例从64%上升至71%,提高了产物的专一性。分析原因可能与取代氨基酸残基的大小及氢键作用力的变化有关。同时,突变酶的酶学性质方面保持了原始酶的嗜热性、热稳定性及耐碱性。
The cyclodextrin glucosyltransferase(CGTase)from the marine Bacillus sp.Y112 was analyzed by homologous modeling and amino acid sequence alignment;it was found that the arginine residue at position 81 from the N-terminus may affect the product specificity.In this study,when this residue was mutated to threonine by site-directed mutagenesis,the yield ofα-CD was decreased,and the percentage ofβ-CD in the cyclization products was increased from 64%to 71%,suggesting the improved product specificity.The underlying reason may be related to the size of the substituted amino acid residue and change in hydrogen bonding interaction.At the same time,the enzymatic properties of the mutant retained the thermophilicity,thermostability,and alkali resistance of the wild-type enzyme.
作者
李晓涵
郭姣梅
宋凯
孙晶晶
王伟
郝建华
LI Xiaohan;GUO Jiaomei;SONG Kai;SUN Jingjing;WANG Wei;HAO Jianhua(College of Food Sciences and Technology,Shanghai Ocean University,Shanghai 201306,China;Key Laboratory of Sustainable Development of Polar Fishery,Ministry of Agriculture and Rural Affairs,Yellow Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences,Qingdao 266071,China;Laboratory for Marine Drugs and Bioproducts,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266071,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2021年第10期133-138,共6页
Food Science
基金
“十三五”国家重点研发计划重点专项(2018YFC0311106)
山东省重点研发计划项目(2019GHY112030)
中国水产科学研究院基本科研业务费资助项目(2020TD67)
青岛市市南科技计划项目(2018-4-002-ZH)。
关键词
环糊精葡萄糖基转移酶
定点突变
环糊精
产物特异性
cyclodextrin glycosyltransferases
site-directed mutagenesis
cyclodextrin
product specificity
