The dinuclear iron-oxo ferroxidase center of Pyrococcus furiosus ferritin is a stable prosthetic group with unexpectedly high reduction potentials.
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.
Tatur
Jana
J
Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
Hagen
Wilfred R
WR
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*
D001426:Bacterial Proteins; D021122:Protein Subunits; D005293:Ferritins; D007501:Iron; D002570:Ceruloplasmin