Institut für Computerphysik, Universität Stuttgart , D-70569 Stuttgart, Germany.
J Phys Chem B. 2014 Jan 23;118(3):771-82. doi: 10.1021/jp410261k. Epub 2014 Jan 8.
We have performed atomistic molecular dynamics simulations to study the solvation characteristics of model spheres for low concentrations of urea and hydroxyectoine in aqueous solution. The spheres are either positively or negatively charged with a valency of one or charge neutral. Our results illustrate that the presence of osmolytes influences the solvation properties of the spheres significantly. We have conducted a detailed investigation of water properties like the mean dipolar relaxation times, water orientation parameters around the spheres, dielectric constants, preferential binding behavior, water self-diffusion coefficients, and free energies of solvation by thermodynamic integration to study the influence of osmolytes in detail. Our findings indicate that several factors like the charge of the spheres as well as the characteristics of the osmolytes significantly influence the thermodynamic and dynamic properties of the local water shell and the solvation process with regard to varying enthalpic and entropic contributions.
我们进行了原子分子动力学模拟，以研究低浓度尿素和羟乙基甜菜碱在水溶液中模型球体的溶剂化特性。这些球体带有一个或一个电荷中性的一价正电荷或负电荷。我们的结果表明，渗透剂的存在显著影响球体的溶剂化性质。我们详细研究了水的性质，如平均偶极弛豫时间、球体周围水的取向参数、介电常数、优先结合行为、水自扩散系数和溶剂化自由能，以详细研究渗透剂的影响。我们的研究结果表明，一些因素，如球体的电荷以及渗透剂的特性，显著影响局部水壳的热力学和动力学性质以及溶剂化过程中关于焓和熵贡献的变化。
