Engineering of cyclodextrin glycosyltransferase reaction and product specificity
نویسندگان
چکیده
منابع مشابه
Engineering of Hydrolysis Reaction Specificity in the Transglycosylase Cyclodextrin Glycosyltransferase
Cyclodextrin glycosyltransferase (CGTase) is a member of the a-amylase family, a large group of enzymes that act on a-glycosidic bonds in starch and related compounds. Over twenty different reaction and product specificities have been found in this family. Although three-dimensional structure elucidation and the biochemical characterization of site-directed mutants have yielded a detailed insig...
متن کاملEngineering of cyclodextrin product specificity and pH optima of the thermostable cyclodextrin glycosyltransferase from Thermoanaerobacterium thermosulfurigenes EM1.
The product specificity and pH optimum of the thermostable cyclodextrin glycosyltransferase (CGTase) from Thermoanaerobacterium thermosulfurigenes EM1 was engineered using a combination of x-ray crystallography and site-directed mutagenesis. Previously, a crystal soaking experiment with the Bacillus circulans strain 251 beta-CGTase had revealed a maltononaose inhibitor bound to the enzyme in an...
متن کاملEngineering cyclodextrin glycosyltransferase into a starch hydrolase with a high exo-specificity.
Cyclodextrin glycosyltransferase (CGTase) enzymes from various bacteria catalyze the formation of cyclodextrins from starch. The Bacillus stearothermophilus maltogenic alpha-amylase (G2-amylase is structurally very similar to CGTases, but converts starch into maltose. Comparison of the three-dimensional structures revealed two large differences in the substrate binding clefts. (i) The loop form...
متن کاملSite-directed mutations in tyrosine 195 of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 affect activity and product specificity.
Tyrosine 195 is located in the center of the active site cleft of cyclodextrin glycosyltransferase (EC 2.4.1.19) from Bacillus circulans strain 251. Alignment of amino acid sequences of CGTases and alpha-amylases, and the analysis of the binding mode of the substrate analogue acarbose in the active site cleft [Strokopytov, B., et al. (1995) Biochemistry 34, (in press)], suggested that Tyr195 pl...
متن کاملHydrophobic amino acid residues in the acceptor binding site are main determinants for reaction mechanism and specificity of cyclodextrin-glycosyltransferase.
Cyclodextrin-glycosyltransferases (CGTases) (EC ) preferably catalyze transglycosylation reactions with glucosyl residues as acceptor, whereas the homologous alpha-amylases catalyze hydrolysis reactions using water as acceptor. This difference in reaction specificity is most likely caused by the acceptor binding site. To investigate this in detail we altered the acceptor site residues Lys-232, ...
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ژورنال
عنوان ژورنال: Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology
سال: 2000
ISSN: 0167-4838
DOI: 10.1016/s0167-4838(00)00233-8