Protein Domain : Ferric iron reductase IPR008090

Type	Family
Description	Iron is essential for growth in both bacteria and mammals. Controlling the amount of free iron in solution is often used as a tactic by hosts to limit invasion of pathogenic microbes; binding iron tightly within protein molecules can accomplish this. Such iron-protein complexes include haem in blood, lactoferrin in tears/saliva, and transferrin in blood plasma. Some bacteria express surface receptors to capture eukaryotic iron-binding compounds, while others have evolved siderophores (enterobactins) to scavenge iron from iron-binding host proteins []. The control of such siderophore gene expression in Escherichia coli is under the regulation of the negative repressor protein FUR []. When complexed with Fe2+, it down-regulates the transcription not only of the siderophore genes, but also of the moieties that release Fe2+ ions bound to the hydrox-amate enterobactin proteins in the microbial cytoplasm [ ]. An example of the latter is FhuF from the Gram-negative microbes Yersinia pestis, Salmonella typhi, and E. coli []. In conjunction with the siderophore system, this gene has been demonstrated to be essential for growth and virulence in pathogenic enterobacteria [].FhuF (Ferric siderophore reductase) is a member of the [2Fe-2S]ferric iron reductase family. However, in place of the symmetrical tetrahedral arrangement at the ferric ironbinding site, an unusual Cys-Cys C-terminal group distorts the site in this protein []. This property makes FhuF inherently unstable, and another setof regulatory genes, designated "suf", is thought to maintain its activity in the cytoplasm. FhuF, involved in the reduction of ferric iron in cytoplasmic ferrioxamine B [], binds both the iron-loaded and the apo forms of ferrichrome [].
Short Name	Fe_iron_reduct