Effect of preillumination on the P‐680+ reduction kinetics in chloride‐free photosystem II membranes

FEBS Letters

Gleiter, Hermann²  Ono, Taka-aki²  Conjeaud, Helene¹  Inoue, Yorinao²  Mathis, Paul¹ 

[1] Service de Biophysique, Département de Biologie, Centre d'Études Nucléaires de Saclay, 91191 Gif-sur-Yvette, France;Solar Energy Research Group, The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-01, Japan

关键词: Oxygen evolution;    S-state transition;    Cl−;    P-680;    Thermoluminescence;    Photosystem II membrane;    PS;    photosystem;    Mes;    4-morpholine-ethanesulfonic acid;    Chl;    chlorophyll;    QA;    primary quinone acceptor of PS II;    Qb;    secondary quinone acceptor of PS II;   

DOI  :  10.1016/0014-5793(86)80745-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The re-reduction course of P-680⁺, the photooxidized PS II primary donor, was measured as a function of excitation number in Cl⁻-depleted PS II membranes. After the 1st and 2nd excitations the signal amplitude of P-680⁺ is small, indicating a submicrosecond reduction of P-680⁺ by Z, the secondary donor of PS II. After the 3rd excitation, however, a larger P-680⁺ signal with a 40–50 μs half-life is observed. The slow decay of this signal is attributed to a back-reaction with a reduced acceptor in the presence of the Z⁺S₂ state on the donor side. The state Z⁺S₂ has a lifetime longer than 300 ms and its formation was found to depend on the presence of the abnormal S₂ state created by the 1st excitation. The P-680 data and thermoluminescence measurements show that the S-state advancement beyond S₂ is blocked in the absence of Cl⁻ and that the Cl⁻-free abnormal S₂ state has a lifetime about 10-times longer than the normal S₂ state.

【 授权许可】

Unknown