1vdc: Difference between revisions

Revision as of 16:34, 21 February 2008

STRUCTURE OF NADPH DEPENDENT THIOREDOXIN REDUCTASE

OverviewOverview

Thioredoxin exists in all organisms and is responsible for the hydrogen transfer to important enzymes for ribonucleotide reduction and the reduction of methionine sulphoxide and sulphate. Thioredoxins have also been shown to regulate enzyme activity in plants and are also involved in the regulation of transcription factors and several other regulatory activities. Thioredoxin is reduced by the flavoenzyme thioredoxin reductase using NADPH. We have now determined the first structure of a eukaryotic thioredoxin reductase, from the plant Arabidopsis thaliana, at 2.5 A resolution. The dimeric A. thaliana thioredoxin reductase is structurally similar to that of the Escherichia coli enzyme, and most differences occur in the loops. Because the plant and E. coli enzymes have the same architecture, with the same dimeric structure and the same position of the redox active disulphide bond, a similar mechanism that involves very large domain rotations is likely for the two enzymes. The subunit is divided into two domains, one that binds FAD and one that binds NADPH. The relative positions of the domains in A. thaliana thioredoxin reductase differ from those of the E. coli reductase. When the FAD domains are superimposed, the NADPH domain of A. thaliana thioredoxin reductase must be rotated by 8 degrees to superimpose on the corresponding domain of the E. coli enzyme. The domain rotation we now observe is much smaller than necessary for the thioredoxin reduction cycle.

About this StructureAbout this Structure

1VDC is a Single protein structure of sequence from Arabidopsis thaliana with and as ligands. Active as Transferred entry: 1.8.1.9, with EC number 1.6.4.5 Known structural/functional Sites: and . Full crystallographic information is available from OCA.

ReferenceReference

Crystal structure of Arabidopsis thaliana NADPH dependent thioredoxin reductase at 2.5 A resolution., Dai S, Saarinen M, Ramaswamy S, Meyer Y, Jacquot JP, Eklund H, J Mol Biol. 1996 Dec 20;264(5):1044-57. PMID:9000629

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 ==Overview==
-Thioredoxin exists in all organisms and is responsible for the hydrogen, transfer to important enzymes for ribonucleotide reduction and the, reduction of methionine sulphoxide and sulphate. Thioredoxins have also, been shown to regulate enzyme activity in plants and are also involved in, the regulation of transcription factors and several other regulatory, activities. Thioredoxin is reduced by the flavoenzyme thioredoxin, reductase using NADPH. We have now determined the first structure of a, eukaryotic thioredoxin reductase, from the plant Arabidopsis thaliana, at, 2.5 A resolution. The dimeric A. thaliana thioredoxin reductase is, structurally similar to that of the Escherichia coli enzyme, and most, differences occur in the loops. Because the plant and E. coli enzymes have, the same architecture, with the same dimeric structure and the same, position of the redox active disulphide bond, a similar mechanism that, involves very large domain rotations is likely for the two enzymes. The, subunit is divided into two domains, one that binds FAD and one that binds, NADPH. The relative positions of the domains in A. thaliana thioredoxin, reductase differ from those of the E. coli reductase. When the FAD domains, are superimposed, the NADPH domain of A. thaliana thioredoxin reductase, must be rotated by 8 degrees to superimpose on the corresponding domain of, the E. coli enzyme. The domain rotation we now observe is much smaller, than necessary for the thioredoxin reduction cycle.
+Thioredoxin exists in all organisms and is responsible for the hydrogen transfer to important enzymes for ribonucleotide reduction and the reduction of methionine sulphoxide and sulphate. Thioredoxins have also been shown to regulate enzyme activity in plants and are also involved in the regulation of transcription factors and several other regulatory activities. Thioredoxin is reduced by the flavoenzyme thioredoxin reductase using NADPH. We have now determined the first structure of a eukaryotic thioredoxin reductase, from the plant Arabidopsis thaliana, at 2.5 A resolution. The dimeric A. thaliana thioredoxin reductase is structurally similar to that of the Escherichia coli enzyme, and most differences occur in the loops. Because the plant and E. coli enzymes have the same architecture, with the same dimeric structure and the same position of the redox active disulphide bond, a similar mechanism that involves very large domain rotations is likely for the two enzymes. The subunit is divided into two domains, one that binds FAD and one that binds NADPH. The relative positions of the domains in A. thaliana thioredoxin reductase differ from those of the E. coli reductase. When the FAD domains are superimposed, the NADPH domain of A. thaliana thioredoxin reductase must be rotated by 8 degrees to superimpose on the corresponding domain of the E. coli enzyme. The domain rotation we now observe is much smaller than necessary for the thioredoxin reduction cycle.
 ==About this Structure==
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 [[Category: Arabidopsis thaliana]]
 [[Category: Single protein]]
-[[Category: Transferred entry: 1.8.1.9]]
+[[Category: Transferred entry: 1 8.1 9]]
 [[Category: Dai, S.]]
 [[Category: Eklund, H.]]
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 [[Category: thioredoxin reductase]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 10:16:53 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:34:11 2008''