Enhancement of α-CGTase thermostability with the addition of calcium or barium ions. (December 2018)

• Record Type: Journal Article
• Authors: Li, Caiming; Chen, Shuangdi; Gu, Zhengbiao; Hong, Yan; Cheng, Li; Li, Zhaofeng
• Is Part Of: Food bioscience. Volume 26(2018)
• Page Start: 139
• Page End: 144
• Publication Date: 2018-12
• Subjects: Cyclodextrin -- Cyclodextrin glucanotransferase -- Metal ions -- Cyclization activity -- Thermostability; Food -- Biotechnology -- Periodicals; Food -- Research -- Periodicals; Aliments -- Biotecnologia -- Revistes; Aliments -- Investigació -- Revistes; Food -- Biotechnology; Food -- Research; Revistes electròniques; Periodicals; 664.005
• DOI: 10.1016/j.fbio.2018.10.006
• Languages: English
• ISSNs: 2212-4292

Abstract

Abstract: The poor thermostability of native cyclodextrin glycosyltransferases (CGTases), which are essential for cyclodextrin production, limits their use in industrial applications. The effects of 4 divalent metal ions (Ca 2+, Ba 2+, Zn 2+, and Mg 2+ ) on the thermostability of the α-CGTase from Paenibacillus macerans JFB05-01 were investigated. The addition of Ca 2+ or Ba 2+ to the α-CGTase solution significantly enhanced the enzyme's thermostability, while the presence of Zn 2+ or Mg 2+ had little effect. The greatest increase in α-CGTase thermostability was obtained with a final concentration of 1.5 mM Ba 2+ or 0.5 mM Ca 2+ . Under these conditions, the α-CGTase solutions retained 56.1 or 29.1%, respectively, of their initial cyclization activity after 120 min at 60 °C. Mechanistic analyses showed that the addition of Ca 2+ or Ba 2+ significantly protected the secondary and tertiary structures of α-CGTase. This study provides a theoretical foundation and a useful strategy for improving the thermostability of enzymes. Highlights: The cyclization activity of the a-CGTase reached a maximum enhancement with 1.0 mM Ca 2+ or 0.3 mM BaM 2+ . The residual activity of the a-CGTase remained the most with 0.5 mM Ca 2+ or 1.5 mM Ba 2+ after 120 min at 60°C. Intrinsic fluorescence spectroscopy showed that Ca 2+ or Ba 2+ protected the tertiary structure of the α-CGTase. Circular dichroism showed that Ca 2+ or Ba 2+ protected the secondary structure of the α-CGTase.