title: Quality control of photosystem II: lipid peroxidation accelerates photoinhibition under excessive illumination.
abstract: Environmental stresses lower the efficiency of photosynthesis and sometimes cause irreversible damage to plant functions. When spinach thylakoids and Photosystem II membranes were illuminated with excessive visible light (100-1,000 µmol photons m(-1) s(-1)) for 10 min at either 20°C or 30°C, the optimum quantum yield of Photosystem II decreased as the light intensity and temperature increased. Reactive oxygen species and endogenous cationic radicals produced through a photochemical reaction at and/or near the reaction center have been implicated in the damage to the D1 protein. Here we present evidence that lipid peroxidation induced by the illumination is involved in the damage to the D1 protein and the subunits of the light-harvesting complex of Photosystem II. This is reasoned from the results that considerable lipid peroxidation occurred in the thylakoids in the light, and that lipoxygenase externally added in the dark induced inhibition of Photosystem II activity in the thylakoids, production of singlet oxygen, which was monitored by electron paramagnetic resonance spin trapping, and damage to the D1 protein, in parallel with lipid peroxidation. Modification of the subunits of the light-harvesting complex of Photosystem II by malondialdehyde as well as oxidation of the subunits was also observed. We suggest that mainly singlet oxygen formed through lipid peroxidation under light stress participates in damaging the Photosystem II subunits.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
authors.forename: Tiffanie
authors.initials: T
authors.lastname: Chan
authors.forename: Yurika
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Pavel
authors.initials: P
authors.lastname: Pospíšil
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Nijo
authors.forename: Anna
authors.initials: A
authors.lastname: Fujiwara
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Taninaka
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Haruka
authors.initials: H
authors.lastname: Hori
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nanba
authors.forename: Aya
authors.initials: A
authors.lastname: Imai
authors.forename: Noriko
authors.initials: N
authors.lastname: Morita
authors.forename: Miho
authors.initials: M
authors.lastname: Yoshioka-Nishimura
authors.forename: Yohei
authors.initials: Y
authors.lastname: Izumi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Hideki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Naoki
authors.initials: N
authors.lastname: Mizusawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Wada
authors.forename: Yasusi
authors.initials: Y
authors.lastname: Yamamoto
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D008027:Light / Q000009:adverse effects*; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism* / Q000528:radiation effects; D015227:Lipid Peroxidation / Q000528:radiation effects; D008315:Malondialdehyde / Q000494:pharmacology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000378:metabolism* / Q000528:radiation effects; D026082:Singlet Oxygen / Q000378:metabolism; D018724:Spinacia oleracea / Q000378:metabolism* / Q000528:radiation effects; D020524:Thylakoids / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D026082:Singlet Oxygen; D008315:Malondialdehyde; D010100:Oxygen