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{{STRUCTURE_2pvd| PDB=2pvd | SCENE= }} | |||
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'''Crystal srtucture of the reduced ferredoxin:thioredoxin reductase''' | '''Crystal srtucture of the reduced ferredoxin:thioredoxin reductase''' | ||
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[[Category: Synechocystis sp.]] | [[Category: Synechocystis sp.]] | ||
[[Category: Dai, S.]] | [[Category: Dai, S.]] | ||
[[Category: | [[Category: Iron-sulfur]] | ||
[[Category: | [[Category: Redox]] | ||
[[Category: | [[Category: Thioredoxin]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 13:52:02 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 13:52, 4 May 2008
Crystal srtucture of the reduced ferredoxin:thioredoxin reductase
OverviewOverview
Oxygen-evolving photosynthetic organisms regulate carbon metabolism through a light-dependent redox signalling pathway. Electrons are shuttled from photosystem I by means of ferredoxin (Fdx) to ferredoxin-thioredoxin reductase (FTR), which catalyses the two-electron-reduction of chloroplast thioredoxins (Trxs). These modify target enzyme activities by reduction, regulating carbon flow. FTR is unique in its use of a [4Fe-4S] cluster and a proximal disulphide bridge in the conversion of a light signal into a thiol signal. We determined the structures of FTR in both its one- and its two-electron-reduced intermediate states and of four complexes in the pathway, including the ternary Fdx-FTR-Trx complex. Here we show that, in the first complex (Fdx-FTR) of the pathway, the Fdx [2Fe-2S] cluster is positioned suitably for electron transfer to the FTR [4Fe-4S] centre. After the transfer of one electron, an intermediate is formed in which one sulphur atom of the FTR active site is free to attack a disulphide bridge in Trx and the other sulphur atom forms a fifth ligand for an iron atom in the FTR [4Fe-4S] centre--a unique structure in biology. Fdx then delivers a second electron that cleaves the FTR-Trx heterodisulphide bond, which occurs in the Fdx-FTR-Trx complex. In this structure, the redox centres of the three proteins are aligned to maximize the efficiency of electron transfer from the Fdx [2Fe-2S] cluster to the active-site disulphide of Trxs. These results provide a structural framework for understanding the mechanism of disulphide reduction by an iron-sulphur enzyme and describe previously unknown interaction networks for both Fdx and Trx (refs 4-6).
About this StructureAbout this Structure
2PVD is a Protein complex structure of sequences from Synechocystis sp.. Full crystallographic information is available from OCA.
ReferenceReference
Structural snapshots along the reaction pathway of ferredoxin-thioredoxin reductase., Dai S, Friemann R, Glauser DA, Bourquin F, Manieri W, Schurmann P, Eklund H, Nature. 2007 Jul 5;448(7149):92-6. PMID:17611542 Page seeded by OCA on Sun May 4 13:52:02 2008