pH dependence of the multiline, manganese EPR signal for the ‘S2’ state in PS II particles

FEBS Letters

Damoder, Reddy¹  Dismukes, G.Charles¹ 

[1] Department of Chemistry, Princeton University, Princeton, NJ 08544, USA

关键词: Photosystem II;    Manganese EPR;    Photosynthetic oxygen evolution;    Photosynthetic water oxidation;    Electron transfer;    S2 multiline EPR signal;   

DOI  :  10.1016/0014-5793(84)81096-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The pH dependence of oxygen evolution rates, 2,6-dichlorophenolindophenol (DCIP) reduction rates and the intensity of the multiline manganese EPR signal associated with the S₂ Kok state has been studied using oxygen-evolving spinach (PS) II particles. The oxygen evolution and DCIP reduction rates are found to be very sensitive to pH, with the maximal rates occuring at pH 6.5–7.0. Both the rate and yield of the S₁ multiline manganese EPR signal intensity, produced by single flash excitation at room temperature or by continuous illumination at 200 K, are found to be independent of pH, indicating that no proton is released from this manganese site during the S₁ → S₁ electron transfer. These results agree with those from other laboratories showing no proton release on this transition, but using techniques monitoring other species.

【 授权许可】

Unknown