A new angle on heat capacity changes in hydrophobic solvation
A new angle on heat capacity changes in hydrophobic solvation
复制标题
DOI：
10.1021/ja029796n
复制
发表时间：
2003-08-13
影响因子：
15
通讯作者：
Sharp, KA
中科院分区：
文献类型：
--
作者：
Gallagher, KR;Sharp, KA
极性和极性基团在水中的不同溶解度对于球状蛋白、脂质膜、核酸和其他特定生物结构通过疏水和亲水作用的自组装是重要的。极性化合物水化后水的热容增加是疏水效应的一个标志，并将其与极性化合物的水化区别开来，极性化合物的水化会导致热容减少。水在极性和极性基团周围的结构是影响其不同溶解度和热容效应的重要因素。结果表明，模拟得到的水的结合部径向/角分布函数揭示了极性基团和极性基团周围的水化结构截然不同：极性基团和极性基团分别存在“低角度氢键”的缺失或过剩。低角度氢键比高角度氢键具有更大的能量波动，对这些差异的分析为热容的相反变化提供了物理原因，并为溶质周围的水结构和疏水效应提供了新的见解。
The differential solubility of polar and apolar groups in water is important for the self-assembly of globular proteins, lipid membranes, nucleic acids, and other specific biological structures through hydrophobic and hydrophilic effects. The increase in water's heat capacity upon hydration of apolar compounds is one signature of the hydrophobic effect and differentiates it from the hydration of polar compounds, which cause a decrease in heat capacity. Water structuring around apolar and polar groups is an important factor in their differential solubility and heat capacity effects. Here, it is shown that joint radial/angular distribution functions of water obtained from simulations reveal quite different hydration structures around polar and apolar groups: polar and apolar groups have a deficit or excess, respectively, of "low angle hydrogen bonds". Low angle hydrogen bonds have a larger energy fluctuation than high angle bonds, and analysis of these differences provides a physical reason for the opposite changes in heat capacity and new insight into water structure around solutes and the hydrophobic effect.