title: The dinuclear iron-oxo ferroxidase center of Pyrococcus furiosus ferritin is a stable prosthetic group with unexpectedly high reduction potentials.
abstract: Recombinant ferritin from Pyrococcus furiosus expressed in Escherichia coli exhibits in EPR monitored redox titrations a mixed valence (Fe(3+)-Fe2+) S=1/2 signal at intermediate potentials that is a high-resolution homolog of the ferroxidase signal previously described for reconstituted horse spleen apo-ferritin. P. furiosus reconstituted apo-ferritin reduced to intermediate potentials exhibits the same mixed-valence signal, which integrates to close to one spin per subunit. The reduction potentials of +210 and +50 mV imply that the iron dimer is a stable prosthetic group with three redox states.
authors.affiliation: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
authors.forename: Jana
authors.initials: J
authors.lastname: Tatur
authors.forename: Wilfred R
authors.initials: WR
authors.lastname: Hagen
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002570:Ceruloplasmin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D005293:Ferritins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020027:Pyrococcus furiosus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D021122:Protein Subunits; D005293:Ferritins; D007501:Iron; D002570:Ceruloplasmin