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PDBsum entry 2reh
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Oxidoreductase
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PDB id
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2reh
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References listed in PDB file
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Key reference
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Title
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Mechanistic and structural analyses of the roles of arg409 and asp402 in the reaction of the flavoprotein nitroalkane oxidase.
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Authors
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P.F.Fitzpatrick,
D.M.Bozinovski,
A.Héroux,
P.G.Shaw,
M.P.Valley,
A.M.Orville.
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Ref.
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Biochemistry, 2007,
46,
13800-13808.
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PubMed id
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Abstract
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The flavoprotein nitroalkane oxidase (NAO) catalyzes the oxidation of primary
and secondary nitroalkanes to the corresponding aldehydes and ketones. The
enzyme is a homologue of acyl-CoA dehydrogenase. Asp402 in NAO has been proposed
to be the active site base responsible for removing the substrate proton in the
first catalytic step; structurally it corresponds to the glutamate which acts as
the base in medium chain acyl-CoA dehydrogenase. In the active site of NAO, the
carboxylate of Asp402 forms an ionic interaction with the side chain of Arg409.
The R409K enzyme has now been characterized kinetically and structurally. The
mutation results in a decrease in the rate constant for proton abstraction of
100-fold. Analysis of the three-dimensional structure of the R409K enzyme,
determined by X-ray crystallography to a resolution of 2.65 A, shows that the
critical structural change is an increase in the distance between the
carboxylate of Asp402 and the positively charged nitrogen in the side chain of
the residue at position 409. The D402E mutation results in a smaller decrease in
the rate constant for proton abstraction of 18-fold. The structure of the D402E
enzyme, determined at 2.4 A resolution, shows that there is a smaller increase
in the distance between Arg409 and the carboxylate at position 402, and the
interaction of this residue with Ser276 is perturbed. These results establish
the critical importance of the interaction between Asp402 and Arg409 for proton
abstraction by nitroalkane oxidase.
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Secondary reference #1
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Title
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Crystal structures of nitroalkane oxidase: insights into the reaction mechanism from a covalent complex of the flavoenzyme trapped during turnover.
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Authors
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A.Nagpal,
M.P.Valley,
P.F.Fitzpatrick,
A.M.Orville.
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Ref.
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Biochemistry, 2006,
45,
1138-1150.
[DOI no: ]
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PubMed id
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