Protein flexibility from discrete molecular dynamics simulations using quasi-physical potentials.

We have applied all atoms discrete molecular dynamics (DMD) based on a quasi-physical potential to study the flexibility of an extended set of proteins for which atomistic MD simulations are available. The method uses pure physical potentials supplemented by information on secondary structure and despite its simplicity is able to reproduce with good accuracy the dynamics of proteins in solution. The method presents a clear improvement with respect to coarse-grained methods based on structure potentials and opens the possibility to explore dynamics of proteins out from the equilibrium and to trace conformational changes induced by interaction of proteins with both small and macromolecular ligands.