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Updated: Apr 21, 2026
Generation of Null Mutants to Elucidate the Role of Bacterial Glycosyltransferases in Bacterial Motility
Published on: March 11, 2022
Mutations in cyclodextrin glycosyltransferase from Bacillus circulans enhance β-cyclization activity and
Min Huang1, Caiming Li, Zhengbiao Gu
1State Key Laboratory of Food Science and Technology, ‡School of Food Science and Technology, and §Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University , Wuxi, Jiangsu 214122, People's Republic of China.
Abstract:
Cyclodextrin glycosyltransferase (EC 2.4.1.19, CGTase) is used to produce cyclodextrins, which are cyclic glucans with many industrial applications. In the present study, the effects of the amino acid residue at position 577, which is located in calcium-binding site III (CaIII), on cyclization activity and cyclodextrin production were investigated by replacing Asp577 in CGTase from Bacillus circulans STB01 with glutamate, arginine, lysine, and histidine. The results showed that mutations D577E and D577R significantly increased the β-cyclization activity. The D577R mutant, in particular, displayed a 30.7% increase in the β-cyclization activity when compared to the wild-type CGTase. Furthermore, under conditions resembling industrial production processes, the D577R and D577E mutants displayed 9.1 and 2.0% enhancement in β-cyclodextrin production, respectively. More importantly, the higher β-cyclization activities resulted in a significant reduction in the amount of mutant protein required during the process. Thus, the two mutants were much more suitable for the industrial production of β-cyclodextrin than the wild-type enzyme.
