Mutations converting cyclodextrin glycosyltransferase from a transglycosylase into a starch hydrolase
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Updated: Sep 16, 2026

High-throughput Screening of Carbohydrate-degrading Enzymes Using Novel Insoluble Chromogenic Substrate Assay Kits
Published on: September 20, 2016
Hans Leemhuis1, Bauke W Dijkstra, Lubbert Dijkhuizen
1Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.
Abstract:
Cyclodextrin glycosyltransferase (CGTase) efficiently catalyzes transglycosylation of oligo-maltodextrins, although the enzyme also has a low hydrolytic activity. Its +2 substrate binding subsite, which contains the conserved Phe184 and Phe260 residues, has been shown to be important for this transglycosylation activity [Nakamura et al. (1994) Biochemistry 33, 9929-9936]. Here we show that the amino acid side chain at position 260 also controls the hydrolytic activity of CGTase. Three Phe260 mutants of Thermoanaerobacterium thermosulfurigenes CGTase were obtained with a higher hydrolytic activity than ever observed before for a CGTase. These Phe260 mutations even changed CGTase from a transglycosylase into a starch hydrolase.
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