Flash induced XANES spectroscopy for the Ca‐depleted Mn‐cluster in the photosynthetic O2‐evolving enzyme

FEBS Letters

Yamaguchi, Hirotaka²  Ono, Taka-aki³  Inoue, Yorinao³  Kusunoki, Masami¹  Noguchi, Takumi³  Oyanagi, Hiroyuki³ 

[1] School of Science and Technology, Meiji University, Kawasaki, Kanagawa 214, Japan;Electrotechnical Laboratory, Tsukuba, Ibaraki 305, Japan;Solar Energy Research Group, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-01, Japan

关键词: O2 evolution;    Mn-cluster;    Photosystem II;    X-ray absorption;    Calcium: EPR;    PS;    photosystem;    OEC;    oxygen evolving complex;    XANES;    X-ray absorption near edge structure;    MES;    2-(N-mor-pholino)-ethanesulfonic acid;   

DOI  :  10.1016/0014-5793(93)80912-E

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Flash-induced changes of the Mn K-edge absorption spectra have been studied in the oxygen-evolving complex depleted of Ca. The Mn K-edge energy for the Ca-depleted S₁-state was lower by 1.5 eV than that for the normal S₁-state. The K-edge energy upshifted by 1 eV after one flash, indicative of an oxidation of Mn. After two flashes, the K-edge was elevated as well by 0.4 eV, and then reached a steady-state high level after continuous illumination where the K-edge energy was higher by 0.9 eV than that after one flash. The results indicate that the Mn-cluster and/or its direct ligand could be oxidized up to two electrons but further events are blocked.

【 授权许可】

Unknown