Mutations enhance β-cyclodextrin specificity of cyclodextrin glycosyltransferase from Bacillus circulans

Zhaofeng Li; Xiaofeng Ban; Zhengbiao Gu; Caiming Li; Min Huang; Yan Hong; Li Cheng

doi:10.1016/j.carbpol.2014.03.015

Mutations enhance β-cyclodextrin specificity of cyclodextrin glycosyltransferase from Bacillus circulans

Carbohydr Polym. 2014 Aug 8:108:112-7. doi: 10.1016/j.carbpol.2014.03.015. Epub 2014 Mar 15.

Authors

Zhaofeng Li¹, Xiaofeng Ban², Zhengbiao Gu³, Caiming Li², Min Huang², Yan Hong¹, Li Cheng⁴

Affiliations

¹ State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 214122, China.
² School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
³ State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 214122, China. Electronic address: zhengbiaogu@jiangnan.edu.cn.
⁴ State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.

PMID: 24751254
DOI: 10.1016/j.carbpol.2014.03.015

Abstract

The effects of amino acid residue at position 31 in the neighborhood of calcium binding site I (CaI) on product specificity of cyclodextrin glycosyltransferase (EC 2.4.1.19, CGTase) were investigated by replacing Ala31 in the CGTase from Bacillus circulans STB01 with arginine, proline, threonine, serine and glycine. The results showed that the mutations A31R, A31P, and A31T resulted in the increases in β-cyclodextrin-forming activity and β-cyclodextrin production, indicating that these mutations enhanced β-cyclodextrin specificity of the CGTase. Especially the mutant A31R displayed approximately 26% increase in β-cyclodextrin production with a concomitant 41% decrease in α-cyclodextrin production when compared to the wild-type CGTase. Thus, it was much more suitable for the industrial production of β-cyclodextrin than the wild-type enzyme. The enhanced β-cyclodextrin specificity of the mutants might be a result of stabilizing CaI, which also suggested that CaI might play an important role in cyclodextrin product specificity of CGTase.

Keywords: Alanine 31; Cyclodextrin; Cyclodextrin glycosyltransferase; Mutation; Product specificity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacillus / enzymology*
Glucosyltransferases / genetics*
Glucosyltransferases / metabolism*
Mutation
beta-Cyclodextrins / metabolism*

Substances

beta-Cyclodextrins
Glucosyltransferases
cyclomaltodextrin glucanotransferase