Abstract
We have recently shown that the nitrogen of atmospheric nitrogen dioxide (NO2) taken up byplants is incorporated into organic nitro-compounds. We investigated nitration of protein tyrosine from Arabidopsis thaliana fumigated with NO2. The extracted proteins were separated by the two-dimensional PAGE, and analyzed by Western blot using anti-nitrotyrosine (NT) antibody. Seven protein spots were detected, and all of them were identified, using the MALDY-TOF MS and peptide mass finger printing (PMF) using MS-Fit program, to be subunits of oxygen-evolving complex (OEC) of photosystem II; PsbP and PsbO. Some protein spots different from PsbP and PsbO reacted with the antibody when the proteins extracted from the isolated chloroplast were separated and identified nitrated as described above. However, the signal intensity of them was weaker than that of PsbP and PsbO. The present results strongly suggest that NO2 fumigation-mediated nitration of tyrosine residues occurs in a protein-specific manner.
