Abstract
Cyclodextrin glycosyltransferase (CGTase) is an enzyme of the alpha-amylase family, which uses a double displacement mechanism to process alpha-linked glucose polymers. We have determined two X-ray structures of CGTase complexes, one with an intact substrate at 2.1 A resolution, and the other with a covalently bound reaction intermediate at 1.8 A resolution. These structures give evidence for substrate distortion and the covalent character of the intermediate and for the first time show, in atomic detail, how catalysis in the alpha-amylase family proceeds by the concerted action of all active site residues.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Bacillus / enzymology
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Binding Sites
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Catalysis
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Crystallization
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Crystallography, X-Ray
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Electrons
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Glucosyltransferases / chemistry*
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Glucosyltransferases / metabolism*
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Hydrogen Bonding
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Models, Chemical
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Models, Molecular
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Molecular Sequence Data
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Oligosaccharides / chemistry
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Oligosaccharides / metabolism
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Protein Binding
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Protein Conformation
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Structure-Activity Relationship
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Trisaccharides / chemistry
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Trisaccharides / metabolism
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alpha-Amylases / chemistry
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alpha-Amylases / metabolism*
Substances
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Oligosaccharides
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Trisaccharides
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maltotriose
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maltononaose
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Glucosyltransferases
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cyclomaltodextrin glucanotransferase
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alpha-Amylases