Cyclodextrin glucanotransferase (CGTase; EC 2.4.1.19) produces cyclodextrin from starch. The CGTase molecule is composed of four globular domains, A, B, C, and D. In order to gain better understanding of the amylolytic and cyclization mechanisms of CGTase, mutant CGTases were constructed from a CGTase gene (cgt1) of Bacillus stearothermophilus NO2. Cgt1-F191Y (Phe at position 191 was replaced by Tyr), Cgt1-F191Y-F255Y, Cgt1-W254V-F255I, Cgt1-W254V, and Cgt1-F255I were constructed for the analysis of the NH2-terminal region. It was revealed that amino acids surrounding a spiral amylose are important for cyclization characteristics and that hydrophobic amino acids just after the Glu catalytic site play an important role in the hydrolysis characteristics of the enzyme. Mutant CGTases Cgt1-T591F and Cgt1-W629F were also constructed to study the role of a second substrate-binding site in domain D, and it was suggested that substrate binding at both domains A and D stabilized the enzyme and optimized cyclodextrin production.
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http://dx.doi.org/10.1128/jb.174.22.7478-7481.1992 | DOI Listing |
Enzyme Microb Technol
January 2025
Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610213, China. Electronic address:
Natural products and their derivatives are precious resources with extensive applications in various industrial fields. Enzymatic glycosylation is an efficient approach for chemical structure diversification and biological activity alternation of natural products. Herein, we reported a stereoselective glycosylation of complex natural product glycosides catalyzed by two carbohydrate-active enzymes (CAZys).
View Article and Find Full Text PDFCarbohydr Polym
February 2025
Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan. Electronic address:
The glucoconjugation between linear chimeric α-(1→4)- and α-(1→6)-glucosidic segments exhibits functional properties throughout their structure. In this study, we enzymatically synthesized three new series of chimeric nonreducing isomaltomegalosaccharides (N-IMS-n/m), each featuring a constant n, α-(1→4)-segment (average degree of polymerization, DP = 22-25) at the nonreducing terminal, and varying m, α-(1→6)-main chain lengths (DP = 7-53). The synthesized compounds-N-IMS-25/7, N-IMS-24/19, and N-IMS-22/53-were compared to amylose (DP = 28) and previous samples of N-IMS-15/35 and D-IMS-28.
View Article and Find Full Text PDFFront Microbiol
November 2024
State Key Laboratory of Biobased Material and Green Papermaking (LBMP), Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, China.
Sci Rep
December 2024
National Engineering Research Center for Biotechnology, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China.
β-cyclodextrin (β-CD) is an important cyclic oligosaccharide, which is widely applicated in foods, environmental protection, and cosmetics, primarily prepared from enzymatic synthesis in traditional industry. However, several challenges persist, including cumbersome processes and difficulties in achieving continuous fermentation and catalysis. This research introduced a biofilm-based immobilized fermentation, integrating with enzyme catalysis system of surface display in Bacillus subtilis.
View Article and Find Full Text PDFInt J Biol Macromol
November 2024
State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China. Electronic address:
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