title: Janus-faced charge recombinations in photosystem II photoinhibition.
abstract: Light-induced damage of the photosynthetic apparatus in plants is an important phenomenon that primarily affects the photosystem II complex. Here, we propose a new model of photoinhibition in which charge recombination processes have a double-faced role: first, photodamage is induced by singlet oxygen, which is produced via interaction with the triplet reaction center chlorophyll ((3)P(680)) arising from the recombination of the charge-separated state between P(680) and the pheophytin electron acceptor ((3)[P(680)(+)Phe(-)]). Second, photoprotection is provided by competition between (3)[P(680)(+)Phe(-)] formation and direct recombination of the (1)[P(680)(+)Phe(-)] and P(680)(+)Q(A)(-) states. The efficiency of these two pathways is under control of the redox potential of the Phe and Q(A) electron acceptors, which is utilized during adaptation to high light conditions.
authors.affiliation: Institute of Plant Biology, Biological Research Center, Szeged, Hungary. imre@brc.hu
authors.forename: Imre
authors.initials: I
authors.lastname: Vass
authors.forename: Krisztian
authors.initials: K
authors.lastname: Cser
mesh_terms: D004579:Electron Transport / Q000528:radiation effects; D004735:Energy Transfer / Q000528:radiation effects; D008954:Models, Biological; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D020524:Thylakoids / Q000378:metabolism / Q000528:radiation effects
chemical_list: D045332:Photosystem II Protein Complex; D010940:Plant Proteins