title: Intermolecular electron transfer in two-iron superoxide reductase: a putative role for the desulforedoxin center as an electron donor to the iron active site.
abstract: Superoxide reductase (SOR) is a superoxide detoxification system present in some microorganisms. Its active site consists of an unusual mononuclear iron center with an FeN4S1 coordination which catalyzes the one-electron reduction of superoxide to form hydrogen peroxide. Different classes of SORs have been described depending on the presence of an additional rubredoxin-like, desulforedoxin iron center, whose function has remained unknown until now. In this work, we investigated the mechanism of the reduction of the SOR iron active site using the NADPH:flavodoxin oxidoreductase from Escherichia coli, which was previously shown to efficiently transfer electrons to the Desulfoarculus baarsii SOR. When present, the additional rubredoxin-like iron center could function as an electronic relay between cellular reductases and the iron active site for superoxide reduction. This electron transfer was mainly intermolecular, between the rubredoxin-like iron center of one SOR and the iron active site of another SOR. These data provide the first experimental evidence for a possible role of the rubredoxin-like iron center in the superoxide detoxifying activity of SOR.
authors: Laboratoire de Chimie et Biologie des Métaux, iRTSV-CEA Grenoble/CNRS/Université Joseph Fourier, 17 Avenue des Martyrs, 38054, Grenoble Cedex 9, France.
authors: Florence
authors: F
authors: Bonnot
authors: Simon
authors: S
authors: Duval
authors: Murielle
authors: M
authors: Lombard
authors: Julien
authors: J
authors: Valton
authors: Chantal
authors: C
authors: Houée-Levin
authors: Vincent
authors: V
authors: Nivière
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