Molecular Dynamics Study on Winter Flounder Antifreeze Protein and its Binding Mechanism

Abstract In order to study the antifreezing mechanism of the HPLC6 antifreeze protein and its structural effects on the antifreezing activity, molecular dynamics simulations for this protein in aqueous solution were carried out at two different temperatures (300 K and 253 K). The results of these simulations showed that the binding mechanism of the antifreeze protein is mainly due to the adsorption of the molecule to the ice crystal surface and thereby inhibiting the ice growth. The hydrogen bonds between the threonine residues and the oxygen atoms in the ice play an important role in this mechanism. Mutation study was carried out to verify the mechanism. In addition, hydrophobic alanine residues are located on the opposite side of threonine residues and they repel water molecules to prevent water molecules from approaching the ice surface.