Molecular characterisation of a bean chloroplastic 2-Cys peroxiredoxin

A 2-Cys peroxiredoxin (Prx) named Pvprx was purified from Phaseolus vulgari s leaves. Cloning and sequencing of the cDNA and of the gene were achieved using degenerated oligonucleotides designed from partial sequences of pepti des and polymerase chain reaction (PCR) techniques. Comparison of the seque nces of the cDNA and of the gene revealed the presence of six introns inter rupting the coding region. Southern blot analysis suggested the existence o f a small Pvprx multigene family in P. vulgaris comprising at least two mem bers. All sequence features of animal and plant 2-Cys Prxs were conserved i n Pvprx. The purified protein was shown to have a protective effect against plasmid DNA cleavage by reactive oxygen species. The targeting to chloropl asts was demonstrated by fusion of its putative transit peptide to the gree n fluorescent protein (GFP). Accumulation of 1.5 and 1.3 kb mRNAs homologou s to two Pvprx specific probes was found in roots, stems and leaves, with a preferential accumulation of 1.5 kb mRNAs in roots and stems. No major cha nges in the level of accumulation of 1.5 and 1.3 kb mRNAs were found in lea ves sprayed with mercuric chloride. (C) 2001 Editions scientifiques et medi cales Elsevier SAS.