title: Escherichia coli RIC is able to donate iron to iron-sulfur clusters.
abstract: Escherichia coli RIC (Repair of Iron Centers) is a diiron protein previously reported to be involved in the repair of iron-sulfur proteins damaged by oxidative or nitrosative stresses, and proposed to act as an iron donor. This possible role of RIC was now examined specifically by evaluating its ability to donate iron ions to apo-iron-sulfur proteins, determining the iron binding constants and assessing the lability of its iron ions. We show, by UV-visible, EPR and resonance Raman spectroscopies that RIC may participate in the synthesis of an iron-sulfur cluster in the apo-forms of the spinach ferredoxin and IscU when in the presence of the sulfide donating system IscS and L-cysteine. Iron binding assays allowed determining the as-isolated and fully reduced RIC dissociation constants for the ferric and ferrous iron of 10-27 M and 10-13 M, respectively. Mössbauer studies revealed that the RIC iron ions are labile, namely when the center is in the mixed-valence redox form as compared with the (μ-oxo) diferric one. Altogether, these results suggest that RIC is capable of delivering iron for the formation of iron-sulfur clusters.
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República (EAN), Oeiras, Portugal.
authors.forename: Lígia S
authors.initials: LS
authors.lastname: Nobre
authors.affiliation: DSV/iRTSV/CBM, UMR 5249 CEA-Université Grenoble I-CNRS/Equipe de Physicochimie des Métaux en Biologie, CEA-Grenoble, France.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Garcia-Serres
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República (EAN), Oeiras, Portugal.
authors.forename: Smilja
authors.initials: S
authors.lastname: Todorovic
authors.affiliation: Technische Universität Berlin, Institut für Chemie, FG Biophysikalische Chemie, Berlin, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Hildebrandt
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República (EAN), Oeiras, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Teixeira
authors.affiliation: DSV/iRTSV/CBM, UMR 5249 CEA-Université Grenoble I-CNRS/Equipe de Physicochimie des Métaux en Biologie, CEA-Grenoble, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Latour
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República (EAN), Oeiras, Portugal.
authors.forename: Lígia M
authors.initials: LM
authors.lastname: Saraiva
mesh_terms: D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005288:Ferredoxins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018724:Spinacia oleracea / Q000737:chemistry; D013455:Sulfur / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D005288:Ferredoxins; D007506:Iron-Sulfur Proteins; C411665:IscU protein, E coli; D010940:Plant Proteins; D011994:Recombinant Proteins; C497162:YtfE protein, E coli; D013455:Sulfur; D007501:Iron; D013437:Carbon-Sulfur Lyases; C080546:cysteine desulfurase; D003545:Cysteine
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