Tian Shan Xi, Sun Xiang, Cao Rui, Yang Jinlong
Hefei National Laboratory for Physical Sciences at Microscale, and Department of Chemical Physics, University of Science and Technology of China, Anhui, China.
J Phys Chem A. 2009 Jan 15;113(2):480-3. doi: 10.1021/jp8092594.
Thermal stabilities of the zwitterionic glycine (zg) combined with water molecules are investigated by both ab initio/RRKM calculations and the thermostatic molecular dynamics (MD) simulations. The microhydrated zg clusters, zg-nw (n = 2, 3; w = water), can transfer to the canonical clusters cg-nw through the rapid intramolecular proton transfers (PT), while the proton is shifted via the intermolecular hydrogen bonds for zg-4w --> cg-4w. Both the MD/solution model simulations and the RRKM calculations indicate that the zg and cg conformers hydrated with more water molecules have their respective higher stabilties and the transformation needs to overcome a certain energy barrier. The thermostatic MD simulations show that the dynamic PT processes are significantly influenced by both the temperatures used in the trajectory simulations and the hydrogen bonding arrangements between glycine and water molecules.
通过从头算/RRKM计算和恒温分子动力学（MD）模拟研究了两性离子甘氨酸（zg）与水分子结合的热稳定性。微水合zg簇zg-nw（n = 2, 3；w = 水）可通过快速分子内质子转移（PT）转变为规范簇cg-nw，而对于zg-4w→cg-4w，质子则通过分子间氢键转移。MD/溶液模型模拟和RRKM计算均表明，水合水分子较多的zg和cg构象体各自具有较高的稳定性，且转变需要克服一定的能垒。恒温MD模拟表明，动态PT过程受轨迹模拟中使用的温度以及甘氨酸与水分子之间的氢键排列的显著影响。
