1vdc: Difference between revisions
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==Overview== | ==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 ... | 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== | ==About this Structure== | ||
1VDC is a | 1VDC is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana] with SO4 and FAD as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Transferred_entry:_1.8.1.9 Transferred entry: 1.8.1.9], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.6.4.5 1.6.4.5] Structure known Active Sites: ACT and FAD. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1VDC OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: thioredoxin reductase]] | [[Category: thioredoxin reductase]] | ||
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