i have modelled one protein by using modeller, after docking protein with suitable ligand, it is interacting with five amino acid residues, then i submitted that complex to 20 ns simulation (Gromacs). after completion of simulation i extracted protein-ligand complex from *trr and *tpr files, it is showing interaction with five amino acid residues but two amino acid residues are different from initial docked structure? what might be the reason for this? is it acceptable?