TWO-DIMENSIONAL ADSORPTION MODEL FOR THERMAL HYSTERESIS ACTIVITY OF BEETLE(Tenerbio moliter) ANTIFREEZE PROTEIN

Antifreeze proteins in many organisms can effectively protect cells from freezing damages. Because of the interaction between antifreeze proteins and ice crystal within the interfacial region, antifreeze proteins prevent the growth of ice crystal and depress the non-equilibrium freezing point of solution below the melting point. Thermal hysteresis(TH), the difference between the melting and freezing temperatures, is used to detect antifreeze activity. Insect antifreeze proteins have higher thermal hysteresis activity than fish antifreeze proteins. The structure of antifreeze protein from beetle Tenerbio moliter is very regular. Based on the structure characteristic of TmAFP, the authers proposed a novel two-dimensional adsorption model between TmAFP and ice crystal surfaces. And thermal hysteresis activies of the various TmAFPs were calculated by using this model. The theoretical results were consistent with the experimental values. The results suggest that ice surface coverage of AFPs is a necessary condition for their TH activity.