Magnetic Properties of [FeFe]-Hydrogenases: A Theoretical Investigation Based on Extended QM and QM/MM Models of the H-Cluster and Its Surroundings
Magnetic Properties of [FeFe]-Hydrogenases: A Theoretical Investigation Based on Extended QM and QM/MM Models of the H-Cluster and Its Surroundings
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DOI：
10.1002/ejic.201001058
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发表时间：
2011-03-01
影响因子：
2.3
通讯作者：
Lubitz, Wolfgang
中科院分区：
文献类型：
--
作者：
Greco, Claudio;Silakov, Alexey;Lubitz, Wolfgang
在目前的贡献，我们报告的磁性的二氢进化酶[FeFe]-氢化酶的理论研究，基于DFT模型的活性位点（H-簇，一个Fe 6S 6组件，包括双核部分直接参与底物结合），和QM/MM模型的整个酶。反铁磁耦合内的H-集团已被视为使用破缺对称的方法，沿着使用不同的密度泛函。g值的计算结果是不同的理论水平和模型的扩展功能。对称性破缺偶联方案的选择也对计算的g值有显著影响，对于活性就绪（H-ox）和CO抑制（H-ox-CO）酶形式。然而，超精细耦合常数计算发现，提供更一致的结果。这使我们能够表明，实验检测到的非成对电子在双核亚群脱硫脱硫弧菌Hox的离域是相容的催化中心和低重量的外源配体，如水分子之间的弱相互作用。
In the present contribution, we report a theoretical investigation of the magnetic properties of the dihydrogen-evolving enzyme [FeFe]-hydrogenase, based on both DFT models of the active site (the H-cluster, a Fe6S6 assembly including a binuclear portion directly involved in substrates binding), and QM/MM models of the whole enzyme. Antiferromagnetic coupling within the H-cluster has been treated using the broken-symmetry approach, along with the use of different density functionals. Results of g value calculations turned out to vary as a function of the level of theory and of the extension of the model. The choice of the broken-symmetry coupling scheme also had a significant influence on the calculated g values, for both the active-ready (H-ox) and the CO-inhibited (H-ox-CO) enzyme forms. However, hyper-fine coupling-constant calculations were found to provide more consistent results. This allowed us to show that the experimentally detected delocalization of an unpaired electron at the binuclear subcluster in Desulfovibrio desulfuricans Hox is compatible with a weak interaction between the catalytic centre and a low-weight exogenous ligand like a water molecule.