hide
Free keywords:
-
Abstract:
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 þ 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.
