甲虫抗冻蛋白热滞活性的二维吸附结合模型

甲虫抗冻蛋白是一种具有规则结构的昆虫抗冻蛋白。在相同浓度条件下,甲虫抗冻蛋白比鱼类抗冻蛋白有更高的热滞活性,目前已成为人们重点研究的一类抗冻蛋白。根据甲虫抗冻蛋白的结构特点及其在冰晶表面的吸附模式,应用二维吸附结合模型计算分析了具有6￣11个β-螺旋(β-helix)结构片段的甲虫抗冻蛋白变体分子,得到了它们的热滞活性随溶液浓度变化的规律,特别是热滞活性与甲虫抗冻蛋白的β-螺旋结构片段数的关系。结果显示,抗冻蛋白在冰晶表面的覆盖度是一个影响其热滞活性的重要因素。

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.