Destabilization by high pH of the S1‐state of the oxygen‐evolving complex in photosystem II particles

FEBS Letters

van Dijk, Minse A.¹  van Gorkom, Hans J.¹  Plijter, Johan J.¹  de Groot, Alex¹ 

[1] Department of Biophysics, Huygens Laboratory of the State University, PO Box 9504, 2300 RA Leiden, The Netherlands

关键词: Oxygen-evolving complex S-state Photosystem II Manganese pH effect Destabilization;    Chl;    chlorophyll;    DCBQ;    2;    5-dichloro-p-benzoquinone;    Mes;    4-morpholineethane sulfonic acid;    PS II;    photosystem II;    Tricine;    N-[2-hydroxy-1;    1-bis(hydroxymethyl)ethyl]glycine;    DCMU;    3-(3';    4'-di-chlorophenyl)-1;    1-dimethylurea;   

DOI  :  10.1016/0014-5793(86)80184-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The S-state distribution in a dark-adapted photosystem II preparation, isolated from spinach chloroplasts, can be changed by pH. The period 4 oscillation of the oxygen-releasing reaction, as measured by UV absorbance changes, is shifted by one flash at pH 8.3. This is not due to the generation of the EPR signal II on the first flash, or to the loss of a positive charge to some other electron donor after the first flashes. It is concluded that at pH 8.3 the S₁-state is reduced to S₀. The half-time of the reduction of S₁ to S₀ is 45 s, and the reduction is reversed in the dark if the pH is readjusted to pH 6.0. The oxygen release at pH 8.3 is irreversibly slowed down to about 3.2 ms.

【 授权许可】

Unknown