Synonyms: an FeS center, an FeS cluster, an [FeS] iron-sulfur center, an [FeS] iron-sulfur cluster, an iron-sulfur center
|Superclasses:||a cofactor → a prosthetic group|
Iron-sulfur clusters are cofators of iron-sulfur proteins and consist of a cluster of two to four iron atoms linked to sulfides, some of which are cysteine residues of the protein.
Several cluster types have been described, including [2Fe-2S] iron-sulfur cluster, [3Fe-3S] iron-sulfur cluster, [3Fe-4S] iron-sulfur cluster and a [4Fe-4S] iron-sulfur cluster. The [3Fe-4S] cluster is relatively rare, and 3Fe/4Fe interconversion may occur with minimal protein reorganization. In another type of Fe-S cluster, known as a Rieske [2Fe-2S] iron-sulfur cluster, two of the 4 cysteine residues that are coordinated with the iron atoms in regular [2Fe-2S] iron-sulfur cluster are substituted by histidine residues. Although the clusters contain several iron atoms, each one usually transfers only one electron, so, for example, a protein with two [4Fe-4S] clusters will usually transfer two electrons.
Small electron transfer proteins that contain only [2Fe-2S] or [4Fe-4S] clusters are called ferredoxins. When Fe-S clusters occur in larger (and sometimes membrane-bound) proteins together with other prosthetic groups and/or metal cofactors, the proteins are designated as complex Fe-S proteins.
In addition to their roles in electron transfer reactions, iron-sulfur clusters are also known to participate in the activation of substrates, the stabilization of radicals and structures, the protection of proteins from enzymes and the storage of iron and sulfur. In addition, they act as sensors of iron, dioxygen, the superoxide ion, and possibly nitric oxide, and participate in gene expression [Park06].
Molecular Weight: 87.907 Daltons
Enzymes activated by an iron-sulfur cluster, sorted by the type of activation, are:
This compound has been characterized as a cofactor or prosthetic group of the following enzymes: nitrate reductase , 71-hydroxychlorophyll a reductase , anthranilate dioxygenase , NAD-dependent formate dehydrogenase , tetrachloroethene-reductive dehalogenase , NAD-dependent formate dehydrogenase , NAD-dependent formate dehydrogenase , methyl viologen-reducing hydrogenase , tetrachloroethene reductive dehalogenase , pyruvate-ferredoxin oxidoreductase , 2-methylcitrate dehydratase , hydrogenase , respiratory arsenate reductase , respiratory arsenate reductase , 2,3-dihydroxy-3-methylvalerate hydro-lyase , 2,3-dihydroxy-isovalerate dehydratase , F420H2 dehydrogenase , thiosulfate reductase , factor F420-reducing hydrogenase , xanthine dehydrogenase , 6-hydroxypseudooxynicotine dehydrogenase , sulfite reductase , methyl-H4MPT:coenzyme M methyltransferase , hydrogenase , methylenetetrahydrofolate reductase , 4-hydroxybutyryl-CoA dehydratase , vinylacetyl-CoA Δ 3-Δ 2-isomerase
Dirmeier98: Dirmeier R, Keller M, Frey G, Huber H, Stetter KO (1998). "Purification and properties of an extremely thermostable membrane-bound sulfur-reducing complex from the hyperthermophilic Pyrodictium abyssi." Eur J Biochem 1998;252(3);486-91. PMID: 9546664
Park06: Park YJ, Yoo CB, Choi SY, Lee HB (2006). "Purifications and characterizations of a ferredoxin and its related 2-oxoacid:ferredoxin oxidoreductase from the hyperthermophilic archaeon, Sulfolobus solfataricus P1." J Biochem Mol Biol 39(1);46-54. PMID: 16466637
Yamamoto83: Yamamoto I, Saiki T, Liu SM, Ljungdahl LG (1983). "Purification and properties of NADP-dependent formate dehydrogenase from Clostridium thermoaceticum, a tungsten-selenium-iron protein." J Biol Chem 258(3);1826-32. PMID: 6822536
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