Abstract
Although metabolism of reactive nitrogen species (RNS) plays critical roles in both modulating NO signaling and anti-RNS protection, little is known, especially in plants, of its biochemistry and molecular biology. RNS cytotoxicity is probably mediated by the formation of peroxynitrite, a potent oxidizing and nitrating agent. We showed that the purified recombinant protein of Arabidopsis 2-Cys peroxiredoxin (2CPRX), originally identified as a hydroperoxide-reducing peroxidase, can scavenge peroxynitrite efficiently. Functional expression of the Arabidopsis 2CPRX in the 2CPRX-deficient yeast resulted in complementation of the hypersensitivity of the mutant to RNS and reactive oxygen species. This provides the first in vivo evidence of the protective role against RNS toxicity of 2CPRX from higher eukaryotes. These results demonstrate a new role of plant 2CPRX as a critical determinant of the resistance to RNS, and support the existence of a plant enzymatic system for RNS metabolism.
(Sakamoto et al. Plant J., in press)
