Gasanov Ralphreed, Aliyeva Samira, Arao Sachiko, Ismailova Aygun, Katsuta Nobuhiro, Kitade Hidetoshi, Yamada Shuji, Kawamori Asako, Mamedov Fikret
Biophysics Laboratory, Institute of Botany, National Academy of Sciences, Patamdar Road 40, Baku AZ-1073, Azerbaijan.
J Photochem Photobiol B. 2007 Feb 1;86(2):160-4. doi: 10.1016/j.jphotobiol.2006.08.008. Epub 2006 Oct 25.
Water splitting activity, the multiline EPR signal associated with S(2)-state of the CaMn(4)-cluster and the fast and slow phases of the induction curve of the millisecond delayed chlorophyll fluorescence from photosystem II (PSII) in the pH range of 4.5-8.5 were studied in the thylakoid membranes and purified PSII particles. It has been found that O(2) evolution and the multiline EPR signal were inhibited at acidic (pK approximately 5.3) and alkaline (pK approximately 8.1) pH values, and were maximal at pH 6.0-7.0. Our results indicate that the loss of O(2) evolution and the S(2)-state multiline EPR signal associated with the decrease of the millisecond delayed chlorophyll fluorescence only in alkaline region (pH 7.0-8.5). Possible correlations of the millisecond delayed chlorophyll fluorescence components with the donor side reactions in PSII are discussed.
在类囊体膜和纯化的光系统II（PSII）颗粒中，研究了在4.5 - 8.5的pH范围内水裂解活性、与CaMn(4) - 簇的S(2) - 状态相关的多线EPR信号以及PSII毫秒延迟叶绿素荧光诱导曲线的快相和慢相。研究发现，在酸性（pK约为5.3）和碱性（pK约为8.1）pH值下，O(2)释放和多线EPR信号受到抑制，而在pH 6.0 - 7.0时最大。我们的结果表明，仅在碱性区域（pH 7.0 - 8.5），O(2)释放的损失以及与毫秒延迟叶绿素荧光降低相关的S(2) - 状态多线EPR信号出现。文中还讨论了PSII中毫秒延迟叶绿素荧光成分与供体侧反应的可能相关性。
