The Arabidopsis thaliana sulfiredoxin is a plastidic cysteine-sulfinic acid reductase involved in the photooxidative stress response.
The 2-cysteine peroxiredoxins (2-Cys-Prxs) are antioxidants that reduce peroxides through a thiol-based mechanism. During catalysis, these ubiquitous enzymes are occasionally inactivated by the substrate-dependent oxidation of the catalytic cysteine to the sulfinic acid (-SO2H) form, and are reactivated by reduction by sulfiredoxin (Srx), an enzyme recently identified in yeast and in mammal cells. In plants, 2-Cys-Prxs constitute the most abundant Prxs and are located in chloroplasts. Here we have characterized the unique Srx gene in Arabidopsis thaliana (AtSrx) from a functional point of view, and analyzed the phenotype of two AtSrx knockout (AtSrx-) mutant lines. AtSrx is a chloroplastic enzyme displaying sulfinic acid reductase activity, as shown by the ability of the recombinant AtSrx to reduce the overoxidized 2-Cys-Prx form in vitro, and by the accumulation of the overoxidized Prx in mutant lines lacking Srx in vivo. Furthermore, AtSrx mutants exhibit an increased tolerance to photooxidative stress generated by high light combined with low temperature. These data establish that, as in yeast and in mammals, plant 2-Cys-Prxs are subject to substrate-mediated inactivation reversed by Srx, and suggest that the 2-Cys-Prx redox status and sulfiredoxin are parts of a signaling mechanism participating in plant responses to oxidative stress.
Rey
Pascal
P
CEA, DSV, DEVM, LEMP, Laboratoire d'Ecophysiologie Moléculaire des Plantes, UMR 6191 CNRS-CEA-Université de la Méditerranée, 13108 Saint-Paul-lez-Durance, Cedex, France. pascal.rey@cea.fr
Bécuwe
Noëlle
N
Barrault
Marie-Bénédicte
MB
Rumeau
Dominique
D
Havaux
Michel
M
Biteau
Benoît
B
Toledano
Michel B
MB
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002736:Chloroplasts / Q000201:enzymology*; D015870:Gene Expression; D006720:Homozygote; D008027:Light; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009154:Mutation; D010084:Oxidation-Reduction; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D054464:Peroxiredoxins; D010641:Phenotype; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D029681:Arabidopsis Proteins; D010544:Peroxidases; D054464:Peroxiredoxins; D050862:Oxidoreductases Acting on Sulfur Group Donors; C520419:sulfiredoxin protein, Arabidopsis