Changes in the Photosystem II complex associated with hydrogen formation in sulfur deprived Chlamydomonas reinhardtii

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• 作者：Alena Volgusheva^c ; Olaf Kruse^b ; Stenbjö ; rn Styring^a ; Fikret Mamedov^a ; ^{fikret.mamedov@kemi.uu.se" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Chl ; chlorophyll ; PQ ; plastoquinone ; PSII ; photosystem II ; QA and QB ; primary and secondary plastoquinone acceptors in photosystem II ; TAP ; tris-acetate-phosphate medium ; YZ and YD ; redox active tyrosines in photosystem II.
• 刊名：Algal Research
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：18
• 期：Complete
• 页码：296-304
• 全文大小：1331 K

文摘

Redox properties of the acceptor side of Photosystem II were studied during H₂ gas production in cells of Chlamydomonas reinhardtii. Flash-induced variable fluorescence changes and thermoluminescence measurements were performed in wild type and Stm6 mutant cells during different stages of sulfur (S)-deprivation. Analysis of the fluorescence decay kinetics indicated that the forward electron transfer on the acceptor side of Photosystem II was dramatically slowed down during the O₂ evolution and O₂ consumption stages and was completely blocked in the anaerobic stage of S-deprivation, thus, indicating a complete reduction of the PQ-pool. During the H₂ formation stage, the forward electron transfer kinetics in the μsec and msec time scale re-appeared indicating partially restored electron flow from Q_A⁻ to Q_B and the PQ-pool. Thermoluminescese measurements fully confirmed the fluorescence kinetic analysis. Activation of hydrogenase in the H₂ formation stage is responsible for re-oxidation of the PQ pool and reactivation of the electron flow which was found to be faster and more efficient on the Stm6 mutant due to the higher amount of functionally preserved Photosystem II.