Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt , D-64287 Darmstadt , Germany.
J Am Chem Soc. 2019 Aug 21;141(33):12948-12956. doi: 10.1021/jacs.9b03469. Epub 2019 Aug 5.
Complex solution environments are ubiquitous in nature. Most life science systems contain hydrated macromolecules whose solubility, function and stability are modulated by several small organic molecules or salts (cosolutes) present simultaneously. This Perspective discusses solvation of mixed cosolutes in water. Recent computer simulations and experiments have shown that nonadditive cosolute effects on the water solubility of thermoresponsive polymers and on protein stability have a common physical origin, rooted in solvent-excluded volume effects determined by mutually enhanced cosolute hydration in bulk. We discuss mixtures of weakly and strongly hydrated salts in the anionic Hofmeister series and mixtures of urea and trimethylamine -oxide. Nonadditive phenomena in these mixtures lead to intriguing effects including consecutive polymer collapse and swelling transitions and counteraction of denaturant-induced protein unfolding. The combination of today's advanced simulation methods and spectroscopy techniques should be used to improve further the understanding of these complex aqueous solubility problems.
复杂溶液环境在自然界中无处不在。大多数生命科学系统都含有水合大分子，其溶解度、功能和稳定性受到同时存在的几种小分子有机分子或盐（共溶剂）的调节。本观点讨论了混合共溶剂在水中的溶剂化作用。最近的计算机模拟和实验表明，非加和性共溶剂对温敏聚合物的水溶性和蛋白质稳定性的影响具有共同的物理起源，其根源在于由相互增强的共溶剂在本体中的水合作用决定的溶剂排斥体积效应。我们讨论了阴离子型 Hofmeister 系列中弱和强水合盐的混合物以及脲和三甲基氧化胺的混合物。这些混合物中的非加和现象导致了有趣的效应，包括连续的聚合物坍塌和溶胀转变以及变性剂诱导的蛋白质展开的拮抗作用。今天先进的模拟方法和光谱技术的结合应该被用来进一步提高对这些复杂的水溶性问题的理解。
