Chloride‐depletion of photosynthetic water oxidase

FEBS Letters

Junge, Wolfgang¹  Lübbers, Karin¹  Drevenstedt, Wolfgang¹ 

[1] Biophysik, Universität Osnabrück, D-49069 Osnabrück, Germany

关键词: Photosynthesis;    Water oxidation;    Chloride;    Proton;    Electrochromism;    P680 reduction;    BBY;    PS II enriched membrane fragments;    BSA;    bovine serum albumin;    Chl;    chlorophyll;    DMBQ;    2;    6 dimethyl-p-benzoquinone;    DNP-INT;    dinitrophenylether of iodonitrothymol;    EDTA;    ethylene diamine tetraacetic acid;    EPR;    electron paramagnetic resonance;    NR;    neutral red;    PS I;    II;    photosystem I;    II;    P680;    primary electron donor of PS II;    P700;    primary electron donor of PS I;    Si;    ith oxidation state of water oxidase according to the Kok-model in controls and;    Si ∗;    in thylakoids perturbed by chloride deficiency;    XANES;    X-ray absorption near edge structure;   

DOI  :  10.1016/0014-5793(93)80825-F

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Chloride depletion blocks the normal four-step progress of photosynthetic water oxidation. We studied proton release in chloride-depleted thylakoids which were dark-adapted and excited by flashing light. Proton release was blocked from the second flash on, possibly leaving an uncompensated positive charge in the catalytic centre. The reduction of P⁺ ₆₈₀ by Tyr_z was still very rapid (⪡ 10 μs). From the third flash on, P⁺ ₆₈₀ was reduced more slowly (), and by an electrogenic back-reaction. The uncompensated positive charge may be the reason why the rapid reduction of P⁺ ₆₈₀ by Tyr_z is prevented and the transmembrane charge-pair recombination is facilitated.

【 授权许可】

Unknown