Electrostatics of the FeS clusters in respiratory complex I
Electrostatics of the FeS clusters in respiratory complex I
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DOI：
10.1016/j.bbabio.2009.05.001
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发表时间：
2009-10-01
影响因子：
4.3
通讯作者：
Stuchebrukhov, Alexei A.
中科院分区：
文献类型：
--
作者：
Couch, Vernon A.;Medvedev, Emile S.;Stuchebrukhov, Alexei A.
呼吸复合体I将电子从NADH转移到泛醌和质子在线粒体膜上的易位结合在一起。详细了解每个氧化还原中心的中点还原电位（E-m）和影响这些电位的因素对于阐明该酶的电子转移机制至关重要。我们给出了配合物I的铁硫（FeS）簇的精确静电相互作用能，以促进与该酶的电子转移（ET）有关的模型的发展和实验的解释。为了计算FeS簇的氧化还原滴定曲线，有必要包括簇之间的相互作用，这反过来可以用来改进E-m值并验证每个簇的光谱分配。讨论了N4、N5和N6a的计算滴定曲线。此外，我们提出了一些初步的发现，在外部施加膜电位的影响下，复合物I的氧化还原中心的静电。提出了一种基于静电参数确定全息配合物中FeS协因子位置的方法。一个简单的静电模型的蛋白质/膜系统检查，以说明可行性我们的假设。(C) 2009 Elsevier B.V.版权所有
Respiratory complex I couples the transfer of electrons from NADH to ubiquinone and the translocation of protons across the mitochondrial membrane. A detailed understanding of the midpoint reduction potentials (E-m) of each redox center and the factors which influence those potentials are critical in the elucidation of the mechanism of electron transfer in this enzyme. We present accurate electrostatic interaction energies for the iron-sulfur (FeS) clusters of complex I to facilitate the development of models and the interpretation of experiments in connection to electron transfer (ET) in this enzyme. To calculate redox titration curves for the FeS clusters it is necessary to include interactions between clusters,which in turn can be used to refine E-m values and validate spectroscopic assignments of each cluster. Calculated titration curves for clusters N4, N5, and N6a are discussed. Furthermore, we present some initial findings on the electrostatics of the redox centers of complex I under the influence of externally applied membrane potentials. A means of determining the location of the FeS cofactors within the holo-complex based on electrostatic arguments is proposed. A simple electrostatic model of the protein/membrane system is examined to illustrate the viability of our hypothesis. (C) 2009 Elsevier B.V. All rights reserved.