Comparison between Experimental and Broken Symmetry Density Functional Theory (BS-DFT) Calculated Electron Paramagnetic Resonance (EPR) Parameters of the S2 State of the Oxygen-Evolving Complex of Photosystem II in Its Native (Calcium) and Strontium-Substituted Form
Comparison between Experimental and Broken Symmetry Density Functional Theory (BS-DFT) Calculated Electron Paramagnetic Resonance (EPR) Parameters of the S2 State of the Oxygen-Evolving Complex of Photosystem II in Its Native (Calcium) and Strontium-Substituted Form
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DOI：
10.1021/acs.jpcb.7b09498
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发表时间：
2017-12-21
影响因子：
3.3
通讯作者：
O'Malley, Patrick J.
中科院分区：
文献类型：
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作者：
Beal, Nathan J.;Corry, Thomas A.;O'Malley, Patrick J.
实验和破缺对称密度泛函理论（BS-DFT）计算的超精细耦合的S-2态的放氧复合物（OEC）之间的比较已经进行。本文研究了Sr取代Ca和两个末端羟基或水配体W_1和W_2的质子化状态对Mn-55、C-13、N-14、O-17和H-1核的超精细耦合的影响。我们的研究结果表明，最好的协议与实验的OEC模型，其中包含一个羟基在W2位置和水分子在W1。对于这个模型之间的协议的计算和实验数据的所有超精细耦合是优秀的。在W1处具有羟基的模型是特别差的模型。Sr取代有轻微的影响，计算超精细耦合与实验测定一致。的超精细耦合的OEC结构中相对较小的变化的敏感性证明了这种方法在细化其空间和电子结构的细节，这是一个必不可少的步骤，在制定一个完整的机制，水氧化的OEC的权力。
A comparison between experimental and Broken Symmetry Density Functional theory (BS-DFT) calculated hyperfine couplings for the S-2 state of the oxygen-evolving complex (OEC) has been performed. The effect of Ca substitution by Sr combined with the protonation state of two terminal hydroxo or aqua ligands, W1 and W2, on the calculated hyperfine couplings of Mn-55, C-13, N-14, O-17, and H-1 nuclei has been investigated. Our findings show best agreement with experiment for OEC models which contain a hydroxide group at the W2 position and a water molecule at W1. For this model the agreement between calculated and experimental data for all hyperfine couplings is excellent. Models with a hydroxide group at W1 are particularly poor models. Sr substitution has a minor influence on calculated hyperfine couplings in agreement with experimental determinations. The sensitivity of the hyperfine couplings to relatively minor changes in the OEC structure demonstrates the power of this methodology in refining the details of its steric and electronic structure which is an essential step in formulating a complete mechanism for water oxidation by the OEC.