Free-Energy Calculations of Ionic Hydration Consistent with the Experimental Hydration Free Energy of the Proton
Free-Energy Calculations of Ionic Hydration Consistent with the Experimental Hydration Free Energy of the Proton
复制标题
离子水合自由能计算与质子实验水合自由能一致
DOI：
10.1021/acs.jpclett.7b01125
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发表时间：
2017
影响因子：
5.7
通讯作者：
van der Spoel David
中科院分区：
文献类型：
--
作者：
Zhang Haiyang;Jiang Yang;Yan Hai;Yin Chunhua;Tan Tianwei;van der Spoel David
分析了计算自由能修正策略和实验质子水合自由能ΔGs*（H+）的选择，以探讨离子水合实验热力学中存在的明显争议。在没有修正的情况下，水合自由能（ΔGhyd）计算与实验结果相匹配，ΔGs*（H+）= −1064 kJ/mol作为参考。使用伽伐尼表面势，得到的（真实的）ΔGhydare与ΔGs*（H+）= −1098 kJ/mol一致。当以特定的方式应用离散溶剂校正时，获得了与−1112 kJ/mol的“一致性”ΔGs*（H+）匹配的Δ Ghid。该分析合理化了使用不同实验参考的离子的Δ Ghid计算的报告。对于中性氨基酸侧链，ΔGhydare独立于水模型，而对于带电物种，由于水模型，Δ Ghyd存在很大差异，这表明离子周围的水的长程有序对ΔGhyd产生重要贡献。当应用一致的修正时，这些差异会显著减小，但为了获得最准确的结果，建议使用属于力场的水模型。
Computational free-energy correction strategies and the choice of experimental proton hydration free energy, ΔGs*(H+), are analyzed to investigate the apparent controversy in experimental thermodynamics of ionic hydration. Without corrections, the hydration free-energy (ΔGhyd) calculations match experiments with ΔGs*(H+) = −1064 kJ/mol as reference. Using the Galvani surface potential the resulting (real) ΔGhydare consistent with ΔGs*(H+) = −1098 kJ/mol. When applying, in an ad hoc manner, the discrete solvent correction, ΔGhydmatching the “consensus” ΔGs*(H+) of −1112 kJ/mol are obtained. This analysis rationalizes reports on ΔGhydcalculations for ions using different experimental references. For neutral amino acid side chains ΔGhydare independent of the water model, whereas there are large differences in ΔGhyddue to the water model for charged species, suggesting that long-range ordering of water around ions yields an important contribution to the ΔGhyd. These differences are reduced significantly when applying consistent corrections, but to obtain the most accurate results it is recommended to use the water model belonging to the force field.