Electronic structural changes of Mn in the oxygen-evolving complex of photosystem II during the catalytic cycle.
Electronic structural changes of Mn in the oxygen-evolving complex of photosystem II during the catalytic cycle.
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DOI：
10.1021/ic4005938
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发表时间：
2013-05-20
影响因子：
4.6
通讯作者：
Yano J
中科院分区：
文献类型：
--
作者：
Glatzel P;Schroeder H;Pushkar Y;Boron T 3rd;Mukherjee S;Christou G;Pecoraro VL;Messinger J;Yachandra VK;Bergmann U;Yano J
用1s2p直接共振非弹性X射线散射(RIXS)谱研究了光系统II(PS II)在S0-S3态的析氧复合体(OEC)。在S态的跃迁过程中，OEC的光谱变化非常细微，表明电子在整个团簇中强烈离域。结果表明，除了锰离子外，配体在氧化还原反应中也起着重要作用。比较了一系列具有不同质子化状态、不同成核性以及有无Ca存在的MnIV配位络合物，特别是与PS II S3态谱的比较，以了解其氧化状态。我们发现，在一系列MnIV模型体系中，电子结构发生了强烈的变化。S3态的光谱与MnIV络合物Mn3IVCa2和saplnMn2IV(OH)2最相似，即Mn二聚体的氧桥质子化和Mn立方结构一角的Ca的存在显示出相似的光谱响应，这表明PSⅡ中的Ca和氧桥的质子化可能引起Mn位电子结构的类似变化。目前的结果强调，仅有形式氧化态的指定不足以理解支配OEC中催化反应的详细电子结构变化。
The oxygen evolving complex (OEC) in Photosystem II (PS II) was studied in the S0 through S3 states using 1s2p direct resonant inelastic X-ray scattering (RIXS) 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 MnIV coordination complexes with different protonation states, nuclearity, and with and without the presence of Ca 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 MnIV model systems. The spectrum of the S3 state best resembles the MnIV complexes, Mn3IVCa2 and saplnMn2IV(OH)2, i.e. the oxo-bridge protonation of Mn dimer complexes and the presence of Ca in one corner of a Mn cubane structure show a similar spectroscopic response, suggesting that Ca in PS II and protonation of the oxo-bridge may give rise to analogous modifications of the electronic structure at the Mn sites. 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.
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影响因子：
15
作者：
BALDWIN, MJ;STEMMLER, TL;PECORARO, VL
通讯作者：
PECORARO, VL
影响因子：
2.8
作者：
Yamanaka, S.;Isobe, H.;Yamaguchi, K.
通讯作者：
Yamaguchi, K.
影响因子：
15
作者：
Westre, TE;Kennepohl, P;Solomon, EI
通讯作者：
Solomon, EI
DOI：
10.1073/pnas.1115290109
发表时间：
2012-02-14
影响因子：
11.1
作者：
Mukherjee, Shreya;Stull, Jamie A.;Christou, George
通讯作者：
Christou, George
影响因子：
15
作者：
Glatzel, P;Bergmann, U;Yachandra, VK
通讯作者：
Yachandra, VK