Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
Phys Rev Lett. 2011 Mar 18;106(11):118102. doi: 10.1103/PhysRevLett.106.118102. Epub 2011 Mar 16.
Folding and unfolding processes are important for the functional capability of polypeptides and proteins. In contrast with a physiological environment (solvated or condensed phases), an in vacuo study provides well-defined "clean room" conditions to analyze the intramolecular interactions that largely control the structure, stability, and folding or unfolding dynamics. Here we show that a proper consideration of van der Waals (vdW) dispersion forces in density-functional theory (DFT) is essential, and a recently developed DFT+vdW approach enables long time-scale ab initio molecular dynamics simulations at an accuracy close to "gold standard" quantum-chemical calculations. The results show that the inclusion of vdW interactions qualitatively changes the conformational landscape of alanine polypeptides, and greatly enhances the thermal stability of helical structures, in agreement with gas-phase experiments.
折叠和展开过程对于多肽和蛋白质的功能能力很重要。与生理环境（溶剂化或凝聚相）相比，真空研究提供了明确的“洁净室”条件，可分析在很大程度上控制结构、稳定性以及折叠或展开动力学的分子内相互作用。在这里，我们表明，在密度泛函理论（DFT）中适当考虑范德华（vdW）色散力是至关重要的，最近开发的 DFT+vdW 方法可实现接近“黄金标准”量子化学计算精度的长时间尺度从头分子动力学模拟。结果表明，vdW 相互作用的包含从定性上改变了丙氨酸多肽的构象景观，并极大地增强了螺旋结构的热稳定性，这与气相实验一致。
