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Multiple Low-Lying States for Compound I of P450cam and Chloroperoxidase Revealed from Multireference Ab Initio QM/MM Calculations

Multiple Low-Lying States for Compound I of P450cam and Chlo...

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中国化学会第27届学术年会

作者：宋金帅 sason shaik The Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry Hebrew University of Jerusalem Givat Ram Campus State Key Laboratory of Physical Chemistry and Chemical Engineering Xiamen University

In this work we employed the multireference ab initio CASPT2/MM approach to systematically study the ground and low-lying excited states of important oxoiron（IV）-porphyrin cation-radical active species Por·+FeIV=O（Cys） in P450cam and CPO, termed Compound I （Cpd I）. Our calculations suggest that except the ferryl triradicaloid state revealed by previous DFT/MM calculations, the ferryl pentaradicaloid quartet state and perferryl FeV doublet and quartet states may be accessible in energy. This result then raises an intriguing question whether those states contribute to the reactivity of Cpd I. In previous work employing DFT/MM approach, it has been found that hydrogen abstraction barrier with ferryl pentaradicaloid quartet state is lower than that with the ferryl triradicaloid state （Altun, A.;shaik, S.;Thiel, W. J. Am. Chem. Soc. 2007, 129, 8978-8987）. Hence definitely further study is required to explore the reactivity of these states at the multireference ab initio QM/MM level. The experiences and insight gained in this study for high valent transition metal state like FeV could be helpful for future successful application of this type of method to other related systems.

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The Selective Reaction Mechanism of Halogenase SyrB2:A QM/MM Study

The Selective Reaction Mechanism of Halogenase SyrB2:A QM/MM...

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中国化学会第十二届全国量子化学会议

作者： Jing Huang Chunsen Li Wei Wu sason shaik The State Key Laboratory of Physical Chemistry of Solid Surfaces Fujian Provincial Key Laboratory of Theoretical and Computational Chemistryand College of Chemistry and Chemical EngineeringXiamen University State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of Sciences Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry The Hebrew University of Jerusalem

The catalytic cycle ofα-ketoglutarate（α-KG）dependent non-heme Fe（Ⅱ）halogenase Syr B2 was studied by hybrid QM/MM *** results show that with the native substrate（L-Thr）,only the quintet spin state contributes to O2 activation and substrate halogenation due to the exchange-enhanced reactivity（EER）in non-heme *** hydroxylation/halogenation selectivity is identified in this work by considering the external protein *** hydrogen bonding effects by the polar amino acids around the active site and substrate play the dominant role in stabilizing the transition state of the halogenation relative to *** such,Syr B2exhibits exclusively the halogenation selectivity.

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How do Enzymes Utilize Reactive OH Radicals?Lessons from Non-Heme HppE and Fenton Systems

How do Enzymes Utilize Reactive OH Radicals?Lessons from Non...

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中国化学会第30届学术年会-第十九分会：化学中的量子与经典动力学

作者： Binju Wang Jiarui Lu Kshatresh Dutta Dubey Geng Dong Wenzhen Lai sason shaik Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry The Hebrew University of Jerusalem Department of Chemistry Renmin University of China

The iron(Ⅳ)-oxo intermediate has been amply established as the principal oxidant in non-heme enzymes and the key player in C-H bond activations and functionalizations. In contrast to this status, our present QM/MM calculations rule out the iron(Ⅳ)-oxo as the reactive species in fosfomycin biosynthesis in HppE enzyme. Thus, our study reveals that the iron(Ⅳ)-oxo species is converted, by protonation of the ion-oxo group, into a more reactive species, the iron-complexed hydroxyl radical(FeⅢ-(HO·)). The so-formed FeⅢ-(HO·) species is much more potent compared to the alternative oxidants, the ferryl and oxyl species, FeⅣ=O and FeⅢ-O·. The FeⅢ-(HO·) species is also highly selective and is the only oxidant that generates the final cis-fosfomycin product. Thus, the present work broadens the landscape of non-heme iron enzymes and makes a connection to Fenton chemistry, with implications on new potential biocatalysts that may harness hydroxyl radicals for C-H bond functionalizations.

关键词： HppE enzyme iron(Ⅳ)-oxo intermediate FeⅢ-(HO·) species fosfomycin biosynthesis C-H bond activations non-heme

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氢提取的价键计算:一种源于价键理论的概括性预言模式

氢提取的价键计算:一种源于价键理论的概括性预言模式

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中国化学会第九届全国量子化学学术会议

作者：苏培锋宋凌春吴玮 Philippe C．Hiberty sason shaik 厦门大学化学化工学院固体表面物理化学国家重点实验室厦门大学化学化工学院固体表面物理化学国家重点实验室厦门大学化学化工学院固体表面物理化学国家重点实验室厦门大学化学化工学院固体表面物理化学国家重点实验室厦门大学化学化工学院固体表面物理化学国家重点实验室

＜正＞本文应用从头算价键方法和价键态相关图（VBSCD）模型研究了卤素和氢分子之间的氢提取反应:H-H+·X．H-X +H·（X=F,Cl,Br,I）。反应能垒和VBSCD的价键参数由呼吸轨道价键方法（BOVB）和价键组态作用方法计算得到。我们结合了VBSC...

＜正＞本文应用从头算价键方法和价键态相关图（VBSCD）模型研究了卤素和氢分子之间的氢提取反应:H-H+·X．H-X +H·（X=F,Cl,Br,I）。反应能垒和VBSCD的价键参数由呼吸轨道价键方法（BOVB）和价键组态作用方法计算得到。我们结合了VBSCD模型和半经验价键理论对这类反应进行了研究,提出了有关能垒和其它价键参数的经验表达式,其计算精度可以和从头算价键计算方法密切吻合。我们认为,能垒和化学反应的吸热性和放热性有关,但最

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