Structural examination of the impact of glycerol on water structure.
Structural examination of the impact of glycerol on water structure.
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DOI：
10.1021/jp2093862
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发表时间：
2012-02
期刊：
影响因子：
--
通讯作者：
J. J. Towey-J.;L. Dougan
中科院分区：
文献类型：
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作者：
J. J. Towey-J.;L. Dougan
糖醇甘油是冷冻保存所必需的，冷冻保存是用于在低温下储存生物分子、细胞或组织的重要过程。甘油的低温保护作用的一个关键假设是甘油分子的作用是改变水分子的氢键结合能力，从而抑制冰的形成。在这项研究中，高分辨率的中子衍射已被用于与氢/氘同位素标记结合，以确定前所未有的详细的稀甘油水溶液的结构。与某些预期相反，在第一近邻水平上，没有观察到水的配位壳层的位置发生变化。然而，在第二相邻水平下，溶液中仅存在少量甘油对水结构的影响与增加压力相同。还发现了比溶液中预期的更多的甘油单体的证据。分离的甘油分子的这种普遍性导致非常良好混合的溶液，其中甘油-水氢键相互作用非常有利。我们的研究结果表明，虽然水的局部结构是相对不受干扰的甘油的存在下，甘油和水之间的氢键网络高度混合。这些结果表明，解释甘油作用的努力不仅应关注局部水结构，还应关注系统中扩展的氢键网络。
The sugar alcohol glycerol is essential for cryopreservation, an important process used for the storage of biological molecules, cells, or tissues at low temperatures. A key hypothesis for the cryoprotective action of glycerol is that the glycerol molecule acts to modify the hydrogen bonding ability of water molecules, thus inhibiting ice formation. In this study, high-resolution neutron diffraction has been used in conjunction with hydrogen/deuterium isotopic labeling to determine with unprecedented detail the structure of a dilute aqueous glycerol solution. Contrary to some expectations, at the first neighbor level no modification in the position of the coordination shell of water is observed. However, at the second neighbor level the presence of only small quantities of glycerol in the solution has the same impact on water structure as increasing the pressure. Evidence is also found of more glycerol monomers than would be expected in the solution. This prevalence of isolated glycerol molecules results in a very well mixed solution with glycerol-water hydrogen bond interactions being very favorable. Our results indicate that while the local structure of water is relatively unperturbed by the presence of glycerol, the hydrogen bonded network is highly mixed between glycerol and water. These results indicate that efforts to explain the action of glycerol should focus on not just local water structure, but the extended hydrogen bonded network in the system.