title: Polyethylene glycols enhance the thermostability of β-cyclodextrin glycosyltransferase from Bacillus circulans.
abstract: We investigated the ability of six polyethylene glycols (PEGs), with molecular weights ranging from 400 to 20,000 Da, to enhance the thermostability of β-cyclodextrin glycosyltransferase (β-CGTase) from Bacillus circulans. We found that PEGs with different molecular weights could activate and stabilize this β-CGTase, but to different degrees. The most significant increase (about 20%) in β-cyclodextrin-forming activity was achieved by adding 10-15% PEG 400. PEGs with low molecular weights also significantly enhanced the thermostability of β-CGTase; 15% PEG 1000 prolonged its half-life at 60°C by 6.5-fold, compared to a control. Fluorescence spectroscopy and circular dichroism analysis indicated that PEGs helped protect the tertiary and secondary structure of β-CGTase, respectively. This study provides an effective approach for improving the thermostability of CGTases and related enzymes.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China.
authors.forename: Caiming
authors.initials: C
authors.lastname: Li
authors.affiliation: School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109-1065, USA.
authors.forename: Tod P
authors.initials: TP
authors.lastname: Holler
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China. Electronic address: zhengbiaogu@jiangnan.edu.cn.
authors.forename: Zhengbiao
authors.initials: Z
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China. Electronic address: zfli@jiangnan.edu.cn.
authors.forename: Zhaofeng
authors.initials: Z
authors.lastname: Li
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D004795:Enzyme Stability; D005964:Glucosyltransferases / Q000737:chemistry*; D006207:Half-Life; D006358:Hot Temperature; D057927:Hydrophobic and Hydrophilic Interactions; D011092:Polyethylene Glycols / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D047392:beta-Cyclodextrins; D011092:Polyethylene Glycols; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase; C031215:betadex
keywords: Cyclodextrin; Cyclodextrin glycosyltransferase; Polyethylene glycol; Thermostability