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PDBsum entry 3a3h
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References listed in PDB file
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Key reference
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Title
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Snapshots along an enzymatic reaction coordinate: analysis of a retaining beta-Glycoside hydrolase.
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Authors
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G.J.Davies,
L.Mackenzie,
A.Varrot,
M.Dauter,
A.M.Brzozowski,
M.Schülein,
S.G.Withers.
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Ref.
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Biochemistry, 1998,
37,
11707-11713.
[DOI no: ]
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PubMed id
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Abstract
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The enzymatic hydrolysis of O-glycosidic linkages is one of the most diverse and
widespread reactions in nature and involves a classic "textbook" enzyme
mechanism. A multidisciplinary analysis of a beta-glycoside hydrolase, the Cel5A
from Bacillus agaradhaerens, is presented in which the structures of each of the
native, substrate, covalent-intermediate, and product complexes have been
determined and their interconversions analyzed kinetically, providing
unprecedented insights into the mechanism of this enzyme class. Substrate is
bound in a distorted 1S3 skew-boat conformation, thereby presenting the anomeric
carbon appropriately for nucleophilic attack as well as satisfying the
stereoelectronic requirements for an incipient oxocarbenium ion. Leaving group
departure results in the trapping of a covalent alpha-glycosyl-enzyme
intermediate in which the sugar adopts an undistorted 4C1 conformation. Finally,
hydrolysis of this intermediate yields a product complex in which the sugar is
bound in a partially disordered mode, consistent with unfavorable interactions
and low product affinity.
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Secondary reference #1
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Title
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Structure of the bacillus agaradherans family 5 endoglucanase at 1.6 a and its cellobiose complex at 2.0 a resolution.
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Authors
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G.J.Davies,
M.Dauter,
A.M.Brzozowski,
M.E.Bjørnvad,
K.V.Andersen,
M.Schülein.
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Ref.
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Biochemistry, 1998,
37,
1926-1932.
[DOI no: ]
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PubMed id
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