Reversible red-ox reactions of the diiron site in the mouse ribonucleotide reductase R2 protein.
The red-ox reactions of the dinuclear iron center of mouse R2 protein upon interaction with different reductants (dithionite alone and with mediators) and oxidants (PES, methylene blue, hydrogen peroxide and para-benzoquinone) have been studied by EPR and optical spectroscopy. The obtained results indicate that the transitions between Fe(III)Fe(III), Fe(II)Fe(III) and Fe(II)Fe(II) states of the dinuclear iron center are reversible and the mu-oxo-bridge may be formed upon oxidation by non-oxygen oxidants. In contrast to the case for the E. coli R2 protein, dithionite alone reduces the tyrosyl radical and diiron center in mouse R2 protein.
Davydov
A
A
Department of Biophysics, Stockholm University, Arrhenius Laboratories, Sweden.
Schmidt
P P
PP
Gräslund
A
A
D000818:Animals; D016227:Benzoquinones / Q000494:pharmacology; D001665:Binding Sites; D004227:Dithionite / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007501:Iron / Q000378:metabolism*; D007700:Kinetics; D008751:Methylene Blue / Q000494:pharmacology; D051379:Mice; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction; D010619:Phenazines / Q000494:pharmacology; D012264:Ribonucleotide Reductases / Q000737:chemistry* / Q000378:metabolism*; D013053:Spectrophotometry
D016227:Benzoquinones; D016877:Oxidants; D010619:Phenazines; C028122:5-ethylphenazine; D004227:Dithionite; C004532:quinone; D006861:Hydrogen Peroxide; D007501:Iron; D012264:Ribonucleotide Reductases; D008751:Methylene Blue