Electronic Structural Changes of Mn in the Oxygen-Evolving Complex of Photosystem II during the Catalytic Cycle

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• 作者：Pieter Glatzel ; Henning Schroeder ; Yulia Pushkar ; Thaddeus Boron ; III ; Shreya Mukherjee ; George Christou ; Vincent L. Pecoraro ; Johannes Messinger ; Vittal K. Yachandra ; Uwe Bergmann ; Junko Yano
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：May 20, 2013
• 年：2013
• 卷：52
• 期：10
• 页码：5642-5644
• 全文大小：217K
• 年卷期：v.52,no.10(May 20, 2013)
• ISSN：1520-510X

文摘

The oxygen-evolving complex (OEC) in photosystem II (PS II) was studied in the S₀ through S₃ states using 1s2p resonant inelastic X-ray scattering spectroscopy. The spectral changes of the OEC during the S-state transitions are subtle, indicating that the electrons are strongly delocalized throughout the cluster. The result suggests that, in addition to the Mn ions, ligands are also playing an important role in the redox reactions. A series of Mn^IV coordination complexes were compared, particularly with the PS II S₃ state spectrum to understand its oxidation state. We find strong variations of the electronic structure within the series of Mn^IV model systems. The spectrum of the S₃ state best resembles those of the Mn^IV complexes Mn₃^IVCa₂ and saplnMn₂^IV(OH)₂. The current result emphasizes that the assignment of formal oxidation states alone is not sufficient for understanding the detailed electronic structural changes that govern the catalytic reaction in the OEC.