Protein conformation and orientation on solid surface is of fundamental importance in the research and development of chromatographic techniques for bioseparation.However,it is difficult to explore the microscopic information using experimental techniques.So,molecular dynamics simulation,a powerful tool with sufficiently small scale in both time and space,has been used to explore the molecular insights into interfacial behavior of protein molecules.First,a model is established to represent the realistic adsorbent surface.Thereafter,protein conformation and orientation on the surface and its implications to the separation performance are shown by molecular dynamics simulations.Repeated adjustment of both protein position and orientation is observed before reaching a stable adsorption.In elution,protein can be desorbed once the protein and ligands carry positive charge by reducing the pH of mobile phase.In both adsorption and desorption,protein unfolding occurs mainly on the ligand surface.Moreover,the effect of ligand parameter has been investigated.High ligand density cause high adsorption capacity.However,the fastest adsorption is observed at a moderate density.Both ligand length and distribution have significant effects on the adsorption irreversibility.Meanwhile,the effect of mobile phase has been investigated.Strong hydrophobic interaction,representing the presence of high-concentration lyotropic salt in mobile phase,can speed up the adsorption but cause protein unfolding more significantly.In elution,low pH is favorable for protein desorption.The simulation results are consistent with experimental results.Moreover,it has provided molecular insight into protein conformation and orientation on the adsorbent surface,