Molecular Dynamics Analysis on the Interaction Among Water, Cations, Anions and Antifreeze Protein

We have carried out molecular dynamics simulation on aqueous solution of winter flounder antifreeze protein with ions or a thin ice layer. It is found that the models of the antifreeze protein and the ions do not affect the motion of water molecules in the case without the ice layer. In the case with the ice layer, the water molecules become less mobile due to the cooling caused by the ice, while the protein becomes more mobile. The protein mobility is consistent with the antifreeze activity of the protein. On the other hand, in the case with the ice layer and the ions, the water molecules become more mobile, and the protein gradually becomes so. This fact is consistent with the cooperative effect of the antifreeze protein and the ions on the lowering of the freezing point.