抗冻蛋白冰水复合体系的分子动力学模拟

Molecular Dynamics Simulation of Antifreeze Protein Ice/Water Composite Systems

抗冻蛋白是一种可以非依数性降低冰点,在低温环境中避免生物体冻伤产生的功能性蛋白.采用分子动力学模拟方法,通过计算体系总能量,从分子层面分析在冰水界面处吸附结合的云杉蚜虫抗冻蛋白、鳕鱼抗冻蛋白和非抗冻蛋白槲寄生毒蛋白对冰水界面的影响.研究结果表明,吸附在冰晶表面上的抗冻蛋白比非抗冻蛋白更容易使界面层体系中固相水分子转变为液相水分子.分析上述三种蛋白质氨基酸序列的亲疏水性特征,发现抗冻蛋白比非抗冻蛋白更容易使冰晶结合面形成类冰水层,诱导冰晶界面层的熔化.

Antifreeze proteins are functional proteins that can reduce the freezing point in nonequilibrium and avoid the freezing injury of organisms in low-temperature environment.The total energy of an ice-water interface system that with two kinds of antifreeze proteins and a kind of nonantifreeze protein(Choristoneura fumiferana(CfAFP),Zoarces americanus(ZaAFP)and non-antifreeze protein Viscum album)have been obtained respectively by using a molecular dynamics simulation method(MD).The effects of these proteins on the ice-water interface are analyzed.The results show that the antifreeze proteins adsorbed on the surface of ice crystals are much more likely to convert water molecules from solid phase into liquid phase water molecules in the interface layer system than non-antifreeze proteins.The hydrophilicity of the three kinds of protein sequences have been analyzed.It is found that antifreeze proteins can much more likely to form an ice-like layer on the ice-bound surface than non-antifreeze proteins,to induce the melting of the ice crystal interface layer.