Hecks B, Wulf K, Breton J, Leibl W, Trissl H W
Abteilung Biophysik, Fachbereich Biologie/Chemie, Universität Osnabrück, Germany.
Biochemistry. 1994 Jul 26;33(29):8619-24. doi: 10.1021/bi00195a001.
A PS I membrane preparation from a PS II deficient mutant of Synechocystis sp. PCC 6803 (psb DI/DII/C) was investigated by picosecond photovoltage and fluorescence measurements. The photovoltage kinetics show two distinct phases. At low excitation energies the fast phase correlates with the fluorescence decay time constant of 22 +/- 4 ps. This phase is ascribed to the trapping of excitons as described by the reaction (AntiP700)* A0-->AntiP700+A0-. In addition to this phase, the photovoltage displays a second rising phase of smaller amplitude with a time constant of 50 +/- 15 ps. We assign the latter phase to further electron transfer from A0 to the secondary acceptor, A1. Assuming the protein as a homogeneous dielectric, our results suggest that the transmembrane distance A0-A1 spans only a small part (20 +/- 8%) of the distance P700-A1.
通过皮秒光电压和荧光测量研究了来自集胞藻6803（psb DI/DII/C）的PS II缺陷突变体的PSI膜制剂。光电压动力学显示出两个不同的阶段。在低激发能量下，快速阶段与22 +/- 4 ps的荧光衰减时间常数相关。该阶段归因于反应（AntiP700）* A0-->AntiP700+A0-所描述的激子捕获。除了这个阶段，光电压还显示出第二个上升阶段，幅度较小，时间常数为50 +/- 15 ps。我们将后一个阶段归因于从A0到次级受体A1的进一步电子转移。假设蛋白质为均匀电介质，我们的结果表明跨膜距离A0-A1仅跨越距离P700-A1的一小部分（20 +/- 8%）。
