College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China.
J Mol Model. 2013 Feb;19(2):601-11. doi: 10.1007/s00894-012-1588-8. Epub 2012 Sep 16.
Molecular dynamic (MD) simulations have been performed to study the behaviors of ten kinds of cyclo-hexa-peptides (CHPs) composed of amino acids with the diverse hydrophilic/hydrophobic side chains at the water/cyclohexane interface. All the CHPs take the "horse-saddle" conformations at the interface and the hydrophilicity/hydrophobicity of the side chains influences the backbones' structural deformations. The orientations and distributions of the CHPs at the interface and the differences of interaction energies (ΔΔE) between the CHPs and the two liquid phases have been determined. RDF analysis shows that the H-bonds were formed between the O(C) atoms of the CHPs' backbones and H(w) atoms of water molecules. N atoms of the CHPs' backbones formed the H-bonds or van der Waals interactions with the water solvent. It was found that there is a parallel relationship between ΔΔE and the lateral diffusion coefficients (D ( xy )) of the CHPs at the interface. The movements of water molecules close to the interface are confined to some extent, indicating that the dynamics of the CHPs and interfacial water molecules are strongly coupled.
已进行分子动力学（MD）模拟，以研究在水/环己烷界面处由具有不同亲水性/疏水性侧链的氨基酸组成的十种环己六肽（CHP）的行为。所有 CHP 在界面处均采用“马鞍”构象，侧链的亲水性/疏水性会影响骨架的结构变形。已确定了界面处 CHP 的取向和分布以及 CHP 与两种液相之间的相互作用能（ΔΔE）的差异。RDF 分析表明，CHP 骨架的 O（C）原子和水分子的 H（w）原子之间形成了氢键。CHP 骨架的 N 原子与水溶剂形成氢键或范德华相互作用。发现ΔΔE 与界面处 CHP 的横向扩散系数（D（xy））之间存在平行关系。靠近界面的水分子的运动在一定程度上受到限制，表明 CHP 和界面水分子的动力学是强耦合的。
