FOOD SCIENCE ›› 2021, Vol. 42 ›› Issue (10): 133-138.doi: 10.7506/spkx1002-6630-20200205-031

• Bioengineering • Previous Articles     Next Articles

Improvement of the Product Specificity of Bacillus sp. Y112 Cyclodextrin Glucosyltransferase by Site-Directed Mutagenesis of Arginine 81

LI Xiaohan, GUO Jiaomei, SONG Kai, SUN Jingjing, WANG Wei, HAO Jianhua,   

  1. (1. College of Food Sciences and Technology, Shanghai Ocean University, Shanghai 201306, China;2. Key Laboratory of Sustainable Development of Polar Fishery, Ministry of Agriculture and Rural A?airs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; 3. Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China)
  • Online:2021-05-25 Published:2021-06-02

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Abstract: 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 of α-CD was decreased, and the percentage of β-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.

Key words: cyclodextrin glycosyltransferases; site-directed mutagenesis; cyclodextrin; product speci?city

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