Physical Chemistry, Dortmund University of Technology, Otto-Hahn-Straße 6, Dortmund, D-44227, Germany.
J Phys Condens Matter. 2011 Apr 20;23(15):155105. doi: 10.1088/0953-8984/23/15/155105. Epub 2011 Mar 31.
The effect of temperature on the connectivity of hydrogen bonds in the hydration shells of the islet amyloid polypeptides (IAPPs) is studied by means of computer simulations. The hydrogen-bonded network of hydration water homogeneously envelopes a peptide at low temperature and breaks into an ensemble of small clusters upon heating. This thermal break occurs via a percolation transition, which is not found to be sensitive to the chemical modifications of IAPP (IAPP with and without a disulfide bridge, human and rat IAPP). The radius of gyration of IAPP starts to increase when the hydration water network breaks upon heating. The fluctuations of the number of intra-peptide hydrogen bonds show negative correlation with the fraction of molecules in the largest cluster of hydration water. The thermal stability of the network of hydration water is enhanced upon increasing number of intra-peptide hydrogen bonds, which makes the peptide surface more hydrophobic. The thermal stabilities of the hydrogen-bonded water networks in the hydration shells of IAPPs and of several other biomolecules are found to be rather similar: the network breaks between 300 and 330 K, i.e., in the temperature interval where the biological activity of living organisms is maximal.
通过计算机模拟研究了温度对胰岛淀粉样多肽（IAPP）水合壳中氢键连通性的影响。在低温下，水合层中的氢键网络均匀地包裹着肽，而在加热时则会破裂成一系列小簇。这种热断裂是通过渗流转变发生的，而这种转变对 IAPP 的化学修饰（有无二硫键的 IAPP、人源和鼠源 IAPP）并不敏感。当水合层中的氢键网络在加热时破裂时，IAPP 的回转半径开始增加。在 IAPP 中，分子内氢键的数量波动与水合层中最大簇的分子分数呈负相关。增加分子内氢键的数量可以增强水合层中氢键网络的热稳定性，从而使肽表面更加疏水。研究发现，IAPP 水合壳中氢键结合水网络和其他几种生物分子的水网络的热稳定性非常相似：网络在 300 到 330 K 之间断裂，即生物活性最大的生物体温度范围内。
