title: Light-triggered selective nitration of PsbO1 in isolated Arabidopsis thylakoid membranes is inhibited by photosynthetic electron transport inhibitors.
abstract: PsbO1 is exclusively nitrated when isolated thylakoid membranes are incubated in a buffer bubbled with nitrogen dioxide (NO2) containing NO2and nitrite. NO2is the primary intermediate for this selective nitration. Isolated thylakoid membranes were incubated in NO2-bubbled buffer at 25°C in the light or dark. Protein analysis confirmed the selective nitration of PsbO1. Illumination was found to be essential in PsbO1 nitration. A nitration mechanism whereby nitratable tyrosine residues of PsbO1 are, prior to nitration, selectively photo-oxidized by photosynthetic electron transport to tyrosyl radicals to combine with NO2to form 3-nitrotyrosine was hypothesized. We tested the electron transport inhibitors 3-(3,4-dichlorophenyl)-1,1- dimethylurea, sodium azide, and 1,5-diphenylcarbazide and found distinct inhibition of nitration of PsbO1. We also propose a possible nitration mechanism.
authors.affiliation: a Department of Mathematical and Life Sciences , Graduate School of Science, Hiroshima University , Kagamiyama, Higashi-Hiroshima , Hiroshima , Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: a Department of Mathematical and Life Sciences , Graduate School of Science, Hiroshima University , Kagamiyama, Higashi-Hiroshima , Hiroshima , Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Shigeto
authors.affiliation: a Department of Mathematical and Life Sciences , Graduate School of Science, Hiroshima University , Kagamiyama, Higashi-Hiroshima , Hiroshima , Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sakamoto
authors.affiliation: a Department of Mathematical and Life Sciences , Graduate School of Science, Hiroshima University , Kagamiyama, Higashi-Hiroshima , Hiroshima , Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Morikawa
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism*; D004579:Electron Transport; D008027:Light; D009573:Nitrites / Q000494:pharmacology; D009585:Nitrogen Dioxide / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D020524:Thylakoids / Q000187:drug effects / Q000378:metabolism*
chemical_list: D009573:Nitrites; D009585:Nitrogen Dioxide
keywords: Arabidopsis; DCMU; DPC; PsbO1; azide; nitrite; nitrogen dioxide; photosynthetic electron transport; protein nitration; redox active