Mamontov E, Sharma V K, Borreguero J M, Tyagi M
Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
J Phys Chem B. 2016 Mar 31;120(12):3232-9. doi: 10.1021/acs.jpcb.6b00866. Epub 2016 Mar 23.
Temperature-dependent onset of apparent anharmonicity in the microscopic dynamics of hydrated proteins and other biomolecules has been known as protein dynamical transition for the last quarter of a century. Using neutron scattering and molecular dynamics simulation, techniques most often associated with protein dynamical transition studies, we have investigated the microscopic dynamics of one of the most common polymers, polystyrene, which was exposed to toluene vapor, mimicking the process of protein hydration from water vapor. Polystyrene with adsorbed toluene is an example of a solvent-solute system, which, unlike biopolymers, is anhydrous and lacks hydrogen bonding. Nevertheless, it exhibits the essential traits of the dynamical transition in biomolecules, such as a specific dependence of the microscopic dynamics of both solvent and host on the temperature and the amount of solvent adsorbed. We conclude that the protein dynamical transition is a manifestation of a universal solvent-solute dynamical relationship, which is not specific to either biomolecules as solute, or aqueous media as solvent, or even a particular type of interactions between solvent and solute.
在过去二十五年里，水合蛋白质及其他生物分子微观动力学中与温度相关的明显非谐性起始现象一直被称为蛋白质动力学转变。我们使用中子散射和分子动力学模拟这两种最常用于蛋白质动力学转变研究的技术，研究了最常见的聚合物之一聚苯乙烯的微观动力学，该聚苯乙烯暴露于甲苯蒸气中，模拟了蛋白质从水蒸气中进行水合的过程。吸附了甲苯的聚苯乙烯是一种溶剂 - 溶质体系的例子，它与生物聚合物不同，是无水的且缺乏氢键。然而，它展现出生物分子动力学转变的基本特征，比如溶剂和主体的微观动力学对温度以及吸附溶剂的量具有特定依赖性。我们得出结论，蛋白质动力学转变是一种普遍的溶剂 - 溶质动力学关系的表现，这种关系并非特定于作为溶质的生物分子、作为溶剂的水性介质，甚至也不是特定于溶剂与溶质之间的某一特定类型的相互作用。
