Redox Potentials and Protonation of the A-Cluster from Acetyl-CoA Synthase. A Density Functional Theory Study
Redox Potentials and Protonation of the A-Cluster from Acetyl-CoA Synthase. A Density Functional Theory Study
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DOI：
10.1021/jp402616e
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发表时间：
2013-11-28
影响因子：
2.9
通讯作者：
Jaworska, Maria
中科院分区：
文献类型：
--
作者：
Chmielowska, Aleksandra;Lodowski, Piotr;Jaworska, Maria
应用密度泛函理论（DFT/BP 86）和极化连续模型（PCM/epsilon = 20）对乙酰辅酶A合酶的A簇进行了计算。对氧化的、单电子和双电子还原的A-簇以及具有在催化循环中重要的配体的A-簇进行了几何优化，即，H2O、CO、CH3、OH-和H+。研究物种的电子结构（自旋密度和NBO电荷）进行了分析，并与使用Wiberg键指数（WBIs）的金属-金属相互作用进行了研究。测定了它们的pK（a）值和还原电位。在计算的基础上，提出了甲基化催化步骤中PCET还原活化A簇的机理。
Density functional theory (DFT/BP86) and the polarized continuum model (PCM/epsilon = 20) have been applied to perform calculations for the A-cluster of acetyl-CoA synthase enzyme. The geometry optimization was carried out for the oxidized, one- and two-electron reduced A-cluster as well as for A-cluster with ligands important in the catalytic cycle, i.e., H2O, CO, CH3, OH-, and H+. The electronic structure of the studied species (spin densities and NBO charges) was analyzed and the metal-metal interactions were investigated with the use of Wiberg bond indices (WBIs). The pK(a) values and the reduction potentials have been determined. On the basis of the calculations, the mechanism of PCET reductive activation of the A-cluster has been proposed for the methylation catalytic step.