• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Interaction of metal ions with biomolecular ligands: How accurate are calculated free energies associated with metal ion complexation?
【24h】

Interaction of metal ions with biomolecular ligands: How accurate are calculated free energies associated with metal ion complexation?

机译：金属离子与生物分子配体的相互作用：与金属离子络合相关的自由能的计算精度如何？

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

To address fundamental questions in bioinorganic chemistry, such as metal ion selectivity, accurate computational protocols for both the gas-phase association of metal-ligand complexes and solvation/desolvation energies of the species involved are needed. In this work, we attempt to critically evaluate the performance of the ab initio and DFT electronic structure methods available and recent solvation models in calculations of the energetics associated with metal ion complexation. On the example of five model complexes ([M~(II)(CH_3S)(H_2O)]~+, [M~(II)(H_2O)_2(H_2S)(NH_3)]~(2+), [M~(II)(CH_3S)(NH_3)(H_2O)(CH_3COO)], [M~(II)(H_2O) 3(SH)(CH_3COO)(Im)], [M~(II)(H_2S)(H_2O)(CH_3COO)(PhOH)(Im)]~+ in typical coordination geometries) and four metal ions (Fe~(2+), Cu~(2+), Zn~(2+), and Cd~(2+); representing open- and closed-shell and the first- and second-row transition metal elements), we provide reference values for the gas-phase complexation energies, as presumably obtained using the CCSD(T)/aug-cc-pVTZ method, and compare them with cheaper methods, such as DFT and RI-MP2, that can be used for large-scale calculations. We also discuss two possible definitions of interaction energies underlying the theoretically predicted metal-ion selectivity and the effect of geometry optimization on these values. Finally, popular solvation models, such as COSMO-RS and SMD, are used to demonstrate whether quantum chemical calculations can provide the overall free enthalpy (ΔG) changes in the range of the expected experimental values for the model complexes or match the experimental stability constants in the case of three complexes for which the experimental data exist. The data presented highlight several intricacies in the theoretical predictions of the experimental stability constants: the covalent character of some metal-ligand bonds (e.g., Cu(II)-thiolate) causing larger errors in the gas-phase complexation energies, inaccuracies in the treatment of solvation of the charged species, and difficulties in the definition of the reference state for Jahn-Teller unstable systems (e.g., [Cu(H_2O)_6]~2+). Although the agreement between the experimental (as derived from the stability constants) and calculated values is often within 5 kcal?mol~(-1), in more complicated cases, it may exceed 15 kcal?mol~(-1). Therefore, extreme caution must be exercised in assessing the subtle issues of metal ion selectivity quantitatively.
机译：为了解决生物无机化学中的基本问题，例如金属离子选择性，需要用于金属-配体络合物的气相缔合和所涉及物质的溶剂化/去溶剂能的精确计算方案。在这项工作中，我们试图在计算与金属离子络合相关的高能学过程中，从头开始评估可用的从头算和DFT电子结构方法以及最新的溶剂化模型的性能。在五个模型复合物（[M〜（II）（CH_3S）（H_2O）]〜+，[M〜（II）（H_2O）_2（H_2S）（NH_3）]〜（2 +），[M〜 （II）（CH_3S）（NH_3）（H_2O）（CH_3COO）]，[M〜（II）（H_2O）3（SH）（CH_3COO）（Im）]，[M〜（II）（H_2S）（H_2O） （CH_3COO）（PhOH）（Im）]〜+在典型的配位几何中）和四种金属离子（Fe〜（2 +），Cu〜（2 +），Zn〜（2+）和Cd〜（2+） ;代表开壳和闭壳以及第一行和第二行过渡金属元素），我们提供了气相络合能的参考值，大概是使用CCSD（T）/ aug-cc-pVTZ方法获得的，并将它们与可用于大规模计算的较便宜的方法（例如DFT和RI-MP2）进行比较。我们还讨论了相互作用能的两种可能的定义，它们是理论上预测的金属离子选择性的基础，以及几何优化对这些值的影响。最后，使用流行的溶剂化模型（例如COSMO-RS和SMD）来证明量子化学计算是否可以在模型配合物的预期实验值范围内提供总自由焓（ΔG）变化或与实验稳定性常数匹配对于存在实验数据的三个配合物。所提供的数据突出了实验稳定性常数的理论预测中的一些复杂之处：某些金属-配体键（例如，铜（II）-硫醇盐）的共价特征导致气相络合能的较大误差，处理中的不准确性带电物质的溶剂化，以及Jahn-Teller不稳定系统（例如[Cu（H_2O）_6]〜2 +）参考状态的定义困难。尽管实验（由稳定性常数得出）与计算值之间的一致性通常在5 kcal？mol〜（-1）以内，但在更复杂的情况下，可能超过15 kcal？mol〜（-1）。因此，在定量评估金属离子选择性的细微问题时必须格外小心。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号