Molecular Dynamics Simulation Of Interaction Between Ih Ice Crystals And Tenebrio Molitor Antifreeze Protein

Antifreeze protein is a wide variety of functional proteins that is adsorbed on the surface of ice crystals and decrease the freezing point in non-colligative way.The freezing point of the antifreeze protein solution is lower than its melting point.This difference is defined as thermal hysteresis value(TH).Adsorption of antifreeze protein on ice crystal surface is an irrevers ible process.Molecular dynamic simulation(MD)has gradually become a powerful tool for studying the microscopic mechanisms at molecular scale.MD experiment were performed that TIP4P-ICE model fitted well with the phase equilibrium curve of ice crystal.Experiments found that there are supercooling and induction periods in the nucleation of ice crystals.From the above,the reliability of MD simulation was acceptable as scientific model construction and operation.In this dissertation,TmAFPs were applied to study the role of additives in inhibiting the ice crystal formation by molecular simulation technology in molecular level.Conventional experiments were performed and the results revealed that the addition of TmAFPs change the phase equilibrium curve of ice crystal.Based on the adsorption-inhibition theory,an irrevers ible model is proposed according to AFPs adsorption kinetics on the ice surface.The influence of water molecules on the TmAFP adsorption on the ice crystal has been considered in this theoretical model.At low supercooling degree,water molecules which add the binding sites on the ice surface are in favor of the adsorption of AFPs.But the ice crystal will be rapidly and uncontrollably growth at high supercooling degree.The calculated results are consistent with the literature data qualitatively.