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| {{STRUCTURE_1rie| PDB=1rie | SCENE= }} | | {{STRUCTURE_1rie| PDB=1rie | SCENE= }} |
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| '''STRUCTURE OF A WATER SOLUBLE FRAGMENT OF THE RIESKE IRON-SULFUR PROTEIN OF THE BOVINE HEART MITOCHONDRIAL CYTOCHROME BC1-COMPLEX'''
| | ===STRUCTURE OF A WATER SOLUBLE FRAGMENT OF THE RIESKE IRON-SULFUR PROTEIN OF THE BOVINE HEART MITOCHONDRIAL CYTOCHROME BC1-COMPLEX=== |
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| ==Overview==
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| BACKGROUND: The 'Rieske' iron-sulfur protein is the primary electron acceptor during hydroquinone oxidation in cytochrome bc complexes. The spectroscopic and electrochemical properties of the 'Rieske' [2Fe-2S] cluster differ significantly from those of other iron-sulfur clusters. A 129-residue water soluble fragment containing the intact [2Fe-2S] cluster was isolated following proteolytic digestion of the bc1 complex and used for structural studies. RESULTS: The structure of the Rieske iron-sulfur fragment containing the reduced [2Fe-2S] cluster has been determined using the multiwavelength anomalous diffraction (MAD) technique and refined at 1.5 A resolution. The fragment has a novel overall fold that includes three sheets of beta strands. The iron atoms of the [2Fe-2S] cluster are coordinated by two cysteine (Fe-1) and two histidine (Fe-2) residues, respectively, with the histidine ligands completely exposed to the solvent. This is in contrast to the four cysteine coordination pattern observed in previously characterised [2Fe-2S] ferredoxins. The cluster-binding fold is formed by two loops connected by a disulfide bridge; these loops superpose with the metal-binding loops of rubredoxins. The environment of the cluster is stabilised by an extensive hydrogen-bond network. CONCLUSIONS: The high-resolution structure supports the proposed coordination pattern involving histidine ligands and provides a basis for a detailed analysis of the spectroscopic and electrochemical properties. As the cluster is located at the tip of the protein, it might come into close contact with cytochrome b. The exposed N epsilon atoms of the histidine ligands of the cluster are readily accessible to quinones and inhibitors within the hydroquinone oxidation (QP) pocket of the bc1 complex and may undergo redox-dependent protonation/deprotonation.
| | The line below this paragraph, {{ABSTRACT_PUBMED_8736555}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 8736555 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_8736555}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Oxidoreductase]] | | [[Category: Oxidoreductase]] |
| [[Category: Rieske iron-sulfur cluster]] | | [[Category: Rieske iron-sulfur cluster]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 07:32:06 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 12:42:40 2008'' |
