Das Mahanta Debasish, Brown Dennis Robinson, Pezzotti Simone, Han Songi, Schwaab Gerhard, Shell M Scott, Havenith Martina
Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum 44780 Bochum Germany
Department of Physics, Technische Universität Dortmund 44227 Dortmund Germany.
Chem Sci. 2023 Jun 16;14(26):7381-7392. doi: 10.1039/d3sc00517h. eCollection 2023 Jul 5.
Glycerol is a major cryoprotective agent and is widely used to promote protein stabilization. By a combined experimental and theoretical study, we show that global thermodynamic mixing properties of glycerol and water are dictated by local solvation motifs. We identify three hydration water populations, , bulk water, bound water (water hydrogen bonded to the hydrophilic groups of glycerol) and cavity wrap water (water hydrating the hydrophobic moieties). Here, we show that for glycerol experimental observables in the THz regime allow quantification of the abundance of bound water and its partial contribution to the mixing thermodynamics. Specifically, we uncover a 1 : 1 connection between the population of bound waters and the mixing enthalpy, which is further corroborated by the simulation results. Therefore, the changes in global thermodynamic quantity - mixing enthalpy - are rationalized at the molecular level in terms of changes in the local hydrophilic hydration population as a function of glycerol mole fraction in the full miscibility range. This offers opportunities to rationally design polyol water, as well as other aqueous mixtures to optimize technological applications by tuning mixing enthalpy and entropy based on spectroscopic screening.
甘油是一种主要的冷冻保护剂，被广泛用于促进蛋白质稳定。通过实验与理论相结合的研究，我们表明甘油和水的整体热力学混合性质由局部溶剂化模式决定。我们确定了三种水合水群体，即本体水、结合水（与甘油亲水基团形成氢键的水）和空穴包裹水（使疏水部分水合的水）。在此，我们表明在太赫兹波段，甘油的实验可观测值能够量化结合水的丰度及其对混合热力学的部分贡献。具体而言，我们发现结合水群体与混合焓之间存在1:1的关系，模拟结果进一步证实了这一点。因此，在完全互溶范围内，整体热力学量——混合焓——的变化在分子水平上可根据局部亲水水合群体随甘油摩尔分数的变化得到合理解释。这为合理设计多元醇 - 水以及其他水性混合物提供了机会，可通过基于光谱筛选调节混合焓和熵来优化技术应用。
