Janus-faced charge recombinations in photosystem II photoinhibition.
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.
Vass
Imre
I
Institute of Plant Biology, Biological Research Center, Szeged, Hungary. imre@brc.hu
Cser
Krisztian
K
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
D045332:Photosystem II Protein Complex; D010940:Plant Proteins