Superoxide reductase from Desulfoarculus baarsii.
نویسندگان
چکیده
Superoxide radical (O2.-) is the univalent reduction product of molecular oxygen and belongs to the group of the so-called toxic oxygen derivatives. For years the only enzymatic system known to catalyze the elimination of superoxide was the superoxide dismutase (SOD), which catalyzes dismutation of superoxide radical anions to hydrogen peroxide and molecular oxygen
منابع مشابه
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 R...
متن کاملFe3+-hydroxide ligation in the superoxide reductase from Desulfoarculus baarsii is associated with pH dependent spectral changes.
Superoxide reductase (SOR) catalyzes the reduction of O2*- to H2O2. Its active site consists of a non-heme Fe2+ center in an unusual square-pyramidal [His4 Cys] coordination. Like many SORs, the electronic absorption band corresponding to the oxidized active site of the SOR from Desulfoarculus baarsii exhibits a pH-dependent alkaline transition changing from ca. 644 to 560 nm as the pH increase...
متن کاملPhotochemical processes observed during the reaction of superoxide reductase from Desulfoarculus baarsii with superoxide: re-evaluation of the reaction mechanism.
Superoxide reductase SOR is an enzyme involved in superoxide detoxification in some microorganisms. Its active site consists of a non-heme ferrous center in an unusual [Fe(NHis)(4) (SCys)(1)] square pyramidal pentacoordination that efficiently reduces superoxide into hydrogen peroxide. In previous works, the reaction mechanism of the SOR from Desulfoarculus baarsii enzyme, studied by pulse radi...
متن کاملReaction of the desulfoferrodoxin from Desulfoarculus baarsii with superoxide anion. Evidence for a superoxide reductase activity.
Desulfoferrodoxin is a small protein found in sulfate-reducing bacteria that contains two independent mononuclear iron centers, one ferric and one ferrous. Expression of desulfoferrodoxin from Desulfoarculus baarsii has been reported to functionally complement a superoxide dismutase deficient Escherichia coli strain. To elucidate by which mechanism desulfoferrodoxin could substitute for superox...
متن کاملSuperoxide reductase from Desulfoarculus baarsii: reaction mechanism and role of glutamate 47 and lysine 48 in catalysis.
Superoxide reductase (SOR) is a small metalloenzyme that catalyzes reduction of O(2)(*)(-) to H(2)O(2) and thus provides an antioxidant mechanism against superoxide radicals. Its active site contains an unusual mononuclear ferrous center, which is very efficient during electron transfer to O(2)(*)(-) [Lombard, M., Fontecave, M., Touati, D., and Nivière, V. (2000) J. Biol. Chem. 275, 115-121]. T...
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ورودعنوان ژورنال:
- Methods in enzymology
دوره 349 شماره
صفحات -
تاریخ انتشار 2002