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Rieske protein is a iron-sulfur protein (ISP) component of cytochrome bc1 complex which was first discovered and isolated by John S. Rieske and co-workers in 1964.
Additional recommended knowledge
Ubiquinol-cytochrome-c reductase (also known as bc1 complex or complex III) is an enzyme complex of bacterial and mitochondrial oxidative phosphorylation systems It catalyses the oxidoreduction of the mobile redox components ubiquinol and cytochrome c, generating an electrochemical potential, which is linked to ATP synthesis. The complex consists of three subunits in most bacteria, and nine in mitochondria: both bacterial and mitochondrial complexes contain cytochrome b and cytochrome c1 subunits, and an iron-sulphur 'Rieske' subunit, which contains a high potential 2Fe-2S cluster.The mitochondrial form also includes six other subunits that do not possess redox centres. Plastoquinone-plastocyanin reductase (b6f complex), present in cyanobacteria and the chloroplasts of plants, catalyses the oxidoreduction of plastoquinol and cytochrome f. This complex, which is functionally similar to ubiquinol-cytochrome c reductase, comprises cytochrome b6, cytochrome f and Rieske subunits.
The Rieske subunit acts by binding either a ubiquinol or plastoquinol anion, transferring an electron to the 2Fe-2S cluster, then releasing the electron to the cytochrome c or cytochrome f haem iron. The rieske domain has a [2Fe-2S] centre. Two conserved cysteines that one Fe ion while the other Fe ion is coordinated by two conserved histidines. The 2Fe-2S cluster is bound in the highly conserved C-terminal region of the Rieske subunit.
Rieske protein family
The homologues of the Rieske proteins include ISP components of cytochrome b6f complex, aromatic-ring-hydroxylating dioxygenases (phthalate dioxygenase, benzene, napthalene and toluene 1,2-dioxygenases) and arsenite oxidase (EC 126.96.36.199). Comparison of amino acid sequences has revealed the following consensus sequence:
The crystal structures of a number of Rieske proteins are known. The overall fold, comprising two subdomains, is dominated by antiparallel β-structure and contains the only α-helix. The smaller "cluster-binding" subdomains in mitochondrial and chloroplast proteins are virtually identical, whereas the large subdomains are substantially different in spite of a common folding topology. The [Fe2S2] cluster-binding subdomains have the topology of an incomplete antiparallel β-barrel. One iron atom of the Rieske [Fe2S2] cluster is coordinated by two cysteine residues and the other is coordinated by two histidine residues through the Nδ atoms. The ligands coordinating the cluster originate from two loops; each loop contributes one Cys and one His.
Human proteins containing this domain
AIFM3; RFESD; UQCRFS1;
Categories: Iron-sulfur proteins | Protein domains | Peripheral membrane proteins
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Rieske_protein". A list of authors is available in Wikipedia.|