Superoxide Réductase

International audienc

Géodynamique andine : résumés étendus = Andean geodynamics : extended abstracts

Dans la région de Chos Malal, le bassin de Neuquen est affecté d'une déformation chevauchante d'âge Paléocène-Eocène. La tectonique tégumentaire a fait intervenir au moins trois niveaux de décollement. Dans un domaine au nord, le socle est affecté de chevauchements profonds, réactivant des failles normales d'âge jurassique. Quelques failles de transfert jurassiques, de direction NE, ont été réactivées sous forme de rampes latérales. La formation du Tromen, volcan quaternaire, a modifié le schéma structural. (Résumé d'auteur

An aromatic hydroxylation reaction catalyzed by a two-component FMN-dependent monooxygenase - The ActVA-ActVB system from streptomyces coelicolor

International audienc

Active deformation of the northern front of the Eastern Great Caucasus

ACTInternational audienc

Geomorphology of the Northern Great Caucasus : investigating depth geometries from surface data

ACTInternational audienc

Detoxification of superoxide without production of H(2)O(2): Antioxidant activity of superoxide reductase complexed with ferrocyanide

The superoxide radical O(2)(·̅) is a toxic by-product of oxygen metabolism. Two O(2)(·̅) detoxifying enzymes have been described so far, superoxide dismutase and superoxide reductase (SOR), both forming H(2)O(2) as a reaction product. Recently, the SOR active site, a ferrous iron in a [Fe(2+) (N-His)(4) (S-Cys)] pentacoordination, was shown to have the ability to form a complex with the organometallic compound ferrocyanide. Here, we have investigated in detail the reactivity of the SOR–ferrocyanide complex with O(2)(·̅) by pulse and γ-ray radiolysis, infrared, and UV-visible spectroscopies. The complex reacts very efficiently with O(2)(·̅). However, the presence of the ferrocyanide adduct markedly modifies the reaction mechanism of SOR, with the formation of transient intermediates different from those observed for SOR alone. A one-electron redox chemistry appears to be carried out by the ferrocyanide moiety of the complex, whereas the SOR iron site remains in the reduced state. Surprisingly, the toxic H(2)O(2) species is no longer the reaction product. Accordingly, in vivoexperiments showed that formation of the SOR–ferrocyanide complex increased the antioxidant capabilities of SOR expressed in an Escherichia coli sodA sodB recA mutant strain. Altogether, these data describe an unprecedented O(2)(·̅) detoxification activity, catalyzed by the SOR–ferrocyanide complex, which does not conduct to the production of the toxic H(2)O(2) species

Kinetic studies of electron transfer between hydrogenase and cytochrome c3 by electrochemistry.

International audienc