Cheng Li-Tien, Xie Yang, Dzubiella Joachim, McCammon J Andrew, Che Jianwei, Li Bo
Department of Mathematics, University of California, San Diego, La Jolla, California 92093-0112, USA.
J Chem Theory Comput. 2009 Feb 10;5(2):257-266. doi: 10.1021/ct800297d.
We construct a variational explicit-solute implicit-solvent model for the solvation of molecules. Central in this model is an effective solvation free-energy functional that depends solely on the position of solute-solvent interface and solute atoms. The total free energy couples altogether the volume and interface energies of solutes, the solute-solvent van der Waals interactions, and the solute-solute mechanical interactions. A curvature dependent surface tension is incorporated through the so-called Tolman length which serves as the only fitting parameter in the model. Our approach extends the original variational implicit-solvent model of Dzubiella, Swanson, and McCammon [Phys. Rev. Lett. 2006, 96, 087802 and J. Chem. Phys. 2006, 124, 084905] to include the solute molecular mechanics. We also develop a novel computational method that combines the level-set technique with optimization algorithms to determine numerically the equilibrium conformation of nonpolar molecules. Numerical results demonstrate that our new model and methods can capture essential properties of nonpolar molecules and their interactions with the solvent. In particular, with a suitable choice of the Tolman length for the curvature correction to the surface tension, we obtain the solvation free energy for a benzene molecule in a good agreement with experimental results.
我们构建了一个用于分子溶剂化的变分显溶质隐溶剂模型。该模型的核心是一个仅依赖于溶质 - 溶剂界面位置和溶质原子的有效溶剂化自由能泛函。总自由能将溶质的体积和界面能、溶质 - 溶剂范德华相互作用以及溶质 - 溶质机械相互作用完全耦合在一起。通过所谓的托尔曼长度引入了曲率相关的表面张力，该长度是模型中唯一的拟合参数。我们的方法扩展了Dzubiella、Swanson和McCammon [《物理评论快报》，2006年，96卷，087802期；《化学物理杂志》，2006年，124卷，084905期] 最初的变分隐溶剂模型，以纳入溶质分子力学。我们还开发了一种新颖的计算方法，该方法将水平集技术与优化算法相结合，以数值确定非极性分子的平衡构象。数值结果表明，我们的新模型和方法能够捕捉非极性分子的基本性质及其与溶剂的相互作用。特别是，通过为表面张力的曲率校正适当选择托尔曼长度，我们得到了苯分子的溶剂化自由能，与实验结果吻合良好。
