Functional analysis and expression characteristics of chloroplastic Prx IIE.
Peroxiredoxins (Prxs) are ubiquitous thiol-dependent peroxidases capable of eliminating a variety of peroxides through reactive catalytic cysteines, which are regenerated by reducing systems. Based on amino acid sequences and their mode of catalysis, five groups of thiol peroxidases have been distinguished in plants, and type II Prx is one of them with representatives in many sub-cellular compartments. The mature form of poplar chloroplastic Prx IIE was expressed as a recombinant protein in Escherichia coli. The protein is able to reduce H2O2 and tert-butyl hydroperoxide and is regenerated by both glutaredoxin (Grx) and thioredoxin (Trx) systems. Nevertheless, compared with Trxs, Grxs, and more especially chloroplastic Grx S12, are far more efficient reductants towards Prx IIE. The expression of Prx IIE at both the mRNA and protein levels as a function of organ type and abiotic stress conditions was investigated. Western blot analysis revealed that Prx IIE gene is constitutively expressed in Arabidopsis thaliana, mostly in young and mature leaves and in flowers. Under photo-oxidative treatment and water deficit, almost no change was observed in the abundance of Prx IIE in A. thaliana, while the level of Prx Q (one of the two other chloroplastic Prxs with 2-Cys Prx) increased in response to both stresses, indicating that plastidic members of the Prx family exhibit specific patterns of expression under stress.
Gama
Filipe
F
Unité Mixte de Recherches 1136 INRA UHP (Interactions Arbres Microorganismes), IFR 110 Génomique Ecophysiologie et Ecologie Fonctionnelles, Université Henri Poincaré BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France.
Bréhélin
Claire
C
Gelhaye
Eric
E
Meyer
Yves
Y
Jacquot
Jean-Pierre
JP
Rey
Pascal
P
Rouhier
Nicolas
N
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002736:Chloroplasts / Q000201:enzymology* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D054477:Glutaredoxins / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D008969:Molecular Sequence Data; D054464:Peroxiredoxins / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013879:Thioredoxins / Q000378:metabolism; D020122:tert-Butylhydroperoxide / Q000378:metabolism
D029681:Arabidopsis Proteins; D054477:Glutaredoxins; D013879:Thioredoxins; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide; D054464:Peroxiredoxins