title: Electronic structural changes of Mn in the oxygen-evolving complex of photosystem II during the catalytic cycle.
abstract: 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(IV)Ca2 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.
authors: European Synchrotron Radiation Facility, 38000 Grenoble, France. pieter.glatzel@esrf.fr
authors: Pieter
authors: P
authors: Glatzel
authors: Henning
authors: H
authors: Schroeder
authors: Yulia
authors: Y
authors: Pushkar
authors: Thaddeus
authors: T
authors: Boron
authors: Shreya
authors: S
authors: Mukherjee
authors: George
authors: G
authors: Christou
authors: Vincent L
authors: VL
authors: Pecoraro
authors: Johannes
authors: J
authors: Messinger
authors: Vittal K
authors: VK
authors: Yachandra
authors: Uwe
authors: U
authors: Bergmann
authors: Junko
authors: J
authors: Yano
mesh_terms: D055162:Biocatalysis; D004583:Electrons; D008345:Manganese / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry* / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry*; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000378:metabolism
chemical_list: D009942:Organometallic Compounds; D045332:Photosystem II Protein Complex; D008345:Manganese; D010100:Oxygen
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