ENDOR study on the position of hydrogens close to the manganese cluster in S2 state of photosystem II

FEBS Letters

Ono, Takaaki²  Inui, Takashi¹  Inoue, Yorinao²  Kawamori, Asako¹ 

[1] Faculty of Science, Kwansei Gkuin University, Nishinomiya 662, Japan;Solar Energy Research Group, Institute of Physical and Chemical Research(Riken), Wako-shi 351-01, Japan

关键词: ENDOR;    Manganese;    ESR signal;    multiline;    Water coordination;    Deuterium substitution;    State S2;    Photosystem II;    (Spinach);    PS;    photosystem;    ENDOR;    electron nuclear double resonance;    Mes;    4-morpholineethanesulfonic acid;    Chl;    chlorophyll;    Mops;    4-morpholinepropanesulfonic acid;    rf;    radiofrequency;   

DOI  :  10.1016/0014-5793(89)81043-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Proton matrix ENDOR of the manganese multiline in the S₂, state of photosystem II membranes from spinach has been investigated. The spectral structure over a range of frequencies of ± 2 MHz centered on the position for a free proton was analyzed through employing a simulation method based on the dipolar interaction between electron and proton magnetic moments. The 6 pairs of lines resolved were attributed to the surrounding proton populations at distances varying within the range 2.7–6.0 Å from the putative manganese center. Two of the 6 pairs, namely those corresponding to protons at distances of 2.7 and 3.2 Å from the manganese center were eliminated on washing of the membranes with deuterated buffer. This suggests that these protons belong to the water molecules coordinating to the manganese cluster. The presence of ethylene glycol instead of glycerol and sucrose in the buffer broadened both EPR and ENDOR spectra. This suggests that ethylene glycol molecules are also accessible to the two-manganese cluster. A possible model of water association to the manganese ions in the photosynthetic water-oxidation system is proposed.

【 授权许可】

Unknown