Identification of iron(III) peroxo species in the active site of the superoxide reductase SOR from Desulfoarculus baarsii.
The active site of superoxide reductase SOR consists of an Fe2+ center in an unusual [His4 Cys1] square-pyramidal geometry. It specifically reduces superoxide to produce H2O2. Here, we have reacted the SOR from Desulfoarculus baarsii directly with H2O2. We have found that its active site can transiently stabilize an Fe3+-peroxo species that we have spectroscopically characterized by resonance Raman. The mutation of the strictly conserved Glu47 into alanine results in a stabilization of this Fe3+-peroxo species, when compared to the wild-type form. These data support the hypothesis that the reaction of SOR proceeds through such a Fe3+-peroxo intermediate. This also suggests that Glu47 might serve to help H2O2 release during the reaction with superoxide.
Mathé
Christelle
C
Laboratoire de Biophysique du Stress Oxydant, SBE/DBJC CEA/SACLAY, 91191 Gif-sur-Yvette Cedex, France.
Mattioli
Tony A
TA
Horner
Olivier
O
Lombard
Murielle
M
Latour
Jean-Marc
JM
Fontecave
Marc
M
Nivière
Vincent
V
D001665:Binding Sites; D020564:Deltaproteobacteria / Q000201:enzymology*; D004578:Electron Spin Resonance Spectroscopy; D005290:Ferric Compounds / Q000737:chemistry* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman
D005290:Ferric Compounds; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; C121849:superoxide reductase