A theoretical study on effect of the initial redox state of cytochrome b₅₅₉ on maximal chlorophyll fluorescence level (F_M): implications for photoinhibition of photosystem II

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• 作者：Lazá ; r ; Du&scaron ; an ; Ilí ; k ; Petr ; Kruk ; Jerzy ; Strzalka ; Kazimierz ; Nau&scaron ; Jan
• 关键词：Cyt ; cytochrome ; DCMU ; 3-(3&prime ; 4&prime ; -dichlorophenyl)-1 ; 1-dimethylurea ; F₀ ; minimal fluorescence ; F_M ; maximal fluorescence ; F_V/F_M ; maximal quantum yield of photosystem II phot
• 刊名：Journal of Theoretical Biology
• 出版年：2005
• 出版时间：March 21, 2005
• 年：2005
• 卷：233
• 期：2
• 页码：287-300
• 全文大小：414 K

文摘

In this work, we extended the reversible radical pair model which describes energy utilization and electron transfer up to the first quinone electron acceptor (Q_A) in photosystem II (PSII), by redox reactions involving cytochrome (cyt) b₅₅₉. In the model, cyt b₅₅₉ accepts electrons from the reduced primary electron acceptor in PSII, pheophytin, and donates electrons to the oxidized primary electron donor in PSII (P680⁺). Theoretical simulations of chlorophyll fluorescence rise based on the model show that the maximal fluorescence, F_M, increases with an increasing amount of initially reduced cyt b₅₅₉. In this work we applied, the first to our knowledge, metabolic control analysis (MCA) to a model of reactions in PSII. The MCA was used to determine to what extent the reactions occurring in the model control the F_M level and how this control depends on the initial redox state of cyt b₅₅₉. The simulations also revealed that increasing the amount of initially reduced cyt b₅₅₉ could protect PSII against photoinhibition. Also experimental data, which might be used to validate our theory, are presented and discussed.