Water based on a molecular model behaves like a hard-sphere solvent for a nonpolar solute when the reference interaction site model and related theories are employed
Water based on a molecular model behaves like a hard-sphere solvent for a nonpolar solute when the reference interaction site model and related theories are employed
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当采用参考相互作用位点模型和相关理论时，基于分子模型的水的行为类似于非极性溶质的硬球溶剂
DOI：
10.1088/0953-8984/28/34/344003
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
M. Kinoshita
中科院分区：
文献类型：
--
作者：
T. Hayashi;H. Oshima;Y. Harano;M. Kinoshita
对于中性硬球溶质，我们比较了介电一致参考相互作用位点模型（DRISM）和角度依赖积分方程（ADIE）理论在等容条件下对溶质周围水的约化密度分布g（r）、溶剂化自由能μ、能量U和熵S的预测.水的分子模型相关的每一个理论被采用。超网链（HNC）闭包被应用于ADIE理论，而HNC和Kovalenko-Hirata（K-H）闭包被应用于DRISM理论.我们还计算了g（r），U，S，和μ的同一溶质在硬球溶剂的分子直径和数密度设置为水，在这种情况下，径向对称积分方程（RSIE）理论。使用形态测量方法（MA）分析μ、U和S对排除体积和溶剂可及表面积的依赖性。ADIE理论的结果与计算机模拟的g（r）、U和μ的结果吻合得更好。对于DRISM理论，溶质附近的g（r）相当高，并且随着溶质直径dU的增加而逐渐变高。相比之下，对于ADIE理论，它要低得多，并且随着d U的增加而变得更低。由于非物理正U和显著较大|S|，DRISM理论的μ变得太高。有趣的是，来自K-H闭包的μ、U和S比来自HNC闭包的更差。总的来说，从DRISM理论与水的分子模型的结果是非常相似的那些从RSIE理论与硬球溶剂。基于MA分析的结果，我们比较讨论了不同的理论方法的情况下，他们被应用于研究蛋白质的溶剂化。
For neutral hard-sphere solutes, we compare the reduced density profile of water around a solute g (r), solvation free energy μ, energy U, and entropy S under the isochoric condition predicted by the two theories: dielectrically consistent reference interaction site model (DRISM) and angle-dependent integral equation (ADIE) theories. A molecular model for water pertinent to each theory is adopted. The hypernetted-chain (HNC) closure is employed in the ADIE theory, and the HNC and Kovalenko–Hirata (K–H) closures are tested in the DRISM theory. We also calculate g (r), U, S, and μ of the same solute in a hard-sphere solvent whose molecular diameter and number density are set at those of water, in which case the radial-symmetric integral equation (RSIE) theory is employed. The dependences of μ, U, and S on the excluded volume and solvent-accessible surface area are analyzed using the morphometric approach (MA). The results from the ADIE theory are in by far better agreement with those from computer simulations available for g (r), U, and μ. For the DRISM theory, g (r) in the vicinity of the solute is quite high and becomes progressively higher as the solute diameter d U increases. By contrast, for the ADIE theory, it is much lower and becomes further lower as d U increases. Due to unphysically positive U and significantly larger| S|, μ from the DRISM theory becomes too high. It is interesting that μ, U, and S from the K–H closure are worse than those from the HNC closure. Overall, the results from the DRISM theory with a molecular model for water are quite similar to those from the RSIE theory with the hard-sphere solvent. Based on the results of the MA analysis, we comparatively discuss the different theoretical methods for cases where they are applied to studies on the solvation of a protein.