Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.
J Phys Chem B. 2010 Sep 9;114(35):11612-9. doi: 10.1021/jp1014912.
Metalloproteins are biomolecular hybrids composed of an "inorganic core" embedded in a "bioorganic matrix". Cofactors typically contain transition metal clusters with complex electronic structure whereas the protein host undergoes dynamics on many length and time scales. This renders computational studies of spectroscopic properties challenging, in particular, when magnetic interactions are involved. In the present study we introduce a simplified description of the antiferromagnetic exchange coupling J in reduced dimensionality which allows one to study magnetostructural dynamics of [2Fe-2S] type iron-sulfur proteins in their oxidized form by molecular dynamics. It is demonstrated that parametrization in terms of a 2D J-surface faithfully reproduces the rigorous results both in vacuo and in Anabaena ferredoxin. In particular, we present a parametrization which relies on a spin-projected density functional approach based on two Kohn-Sham determinants corrected for self-interaction via a self-consistent linear-response Hubbard-U technique. This yields an average J for Anabaena Fd in close agreement with experimental in vitro results without any specific adjustment or fitting. The analytical J-surface can be used for [2Fe-2S] proteins in their oxidized form in general and the idea can be extended to other metalloproteins as well as to other spectroscopic properties.
金属蛋白是由嵌入“生物有机基质”中的“无机核”组成的生物分子杂合体。辅助因子通常包含具有复杂电子结构的过渡金属簇，而蛋白质主体在许多长度和时间尺度上经历动力学变化。这使得光谱性质的计算研究具有挑战性，特别是在涉及磁相互作用时。在本研究中，我们引入了一种简化的描述，即在低维空间中反铁磁交换耦合 J，这使得通过分子动力学研究[2Fe-2S]型铁硫蛋白在其氧化形式下的磁结构动力学成为可能。结果表明，根据 2D J 面的参数化，无论是在真空中还是在鱼腥蓝菌铁氧还蛋白中，都能忠实地再现严格的结果。特别是，我们提出了一种参数化方法，该方法依赖于基于两个 Kohn-Sham 行列式的自旋投影密度泛函方法，通过自洽线性响应 Hubbard-U 技术对自相互作用进行修正。这使得鱼腥蓝菌 Fd 的平均 J 与体外实验结果非常吻合，而无需任何特定的调整或拟合。分析性 J 面可用于一般氧化形式的[2Fe-2S]蛋白，并且该想法也可以扩展到其他金属蛋白以及其他光谱性质。
