Characterization of plant sulfiredoxin and role of sulphinic form of 2-Cys peroxiredoxin
| Autor: | Sergio Barranco-Medina, Francisco Javier Lopez-Jaramillo, Juan-José Lázaro, Iván Iglesias-Baena, Francisca Sevilla, Alfonso Lázaro-Payo |
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| Rok vydání: | 2010 |
| Předmět: |
Physiology
Blotting Western Mutant Arabidopsis hydrogen peroxide Plant Science Polymerase Chain Reaction Arabidopsis thaliana Oxidoreductases Acting on Sulfur Group Donors chemistry.chemical_classification biology Arabidopsis Proteins inorganic phosphate Antioxidant defence Mutagenesis Peas peroxiredoxin Peroxiredoxins Plants Genetically Modified biology.organism_classification Research Papers sulfiredoxin Amino acid Kinetics Sulfiredoxin chemistry Biochemistry Mutagenesis Site-Directed Electrophoresis Polyacrylamide Gel Peroxiredoxin Cysteine |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 0022-0957 |
| Popis: | The antioxidant function of 2-Cys peroxiredoxin (Prx) involves the oxidation of its conserved peroxidatic cysteine to sulphenic acid that is recycled by a reductor agent. In conditions of oxidative stress, the peroxidatic cysteine can be overoxidized to sulphinic acid inactivating the Prx. An enzyme recently discovered, named sulfiredoxin (Srx), reduces the sulphinic 2-Cys Prx (Prx-SO(2)H). To explore the physiological functions of Srx in plants we have cloned, expressed and purified to homogeneity a Srx from Arabidopsis thaliana (AtSrx), as well as five variants by site-directed mutagenesis on amino acids involved in its activity. The activity of sulfiredoxin, determined by a new method, is dependent on the concentration of the sulphinic form of Prx and the conserved Srx is capable of regenerating the functionality of both pea and Arabidopsis Prx-SO(2)H. Molecular modelling of AtSrx and the facts that the R28Q variant shows a partial inactivation, that the activity of the E76A variant is equivalent to that of the native enzyme and that the double mutation R28Q/E76A abolishes the enzymatic activity suggests that the pair His100-Glu76 may be involved in the activation of C72 in the absence of R28. The knock-out mutant plants without Srx or 2-Cys Prx exhibited phenotypical differences under growth conditions of 16 h light, probably due to the signalling role of the sulphinic form of Prx. These mutants showed more susceptibility to oxidative stress than wild-type plants. This work presents the first systematic biochemical characterization of the Srx/Prx system from plants and contributes to a better understanding of its physiological function. |
| Databáze: | OpenAIRE |
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