Cold-adapted organisms produce antifreeze proteins and glycoproteins to control the growth, melting and recrystallization of ice. It has been proposed that these molecules pin the crystal surface, creating a curvature that arrests the growth and melting of the crystal. Here we use thermodynamic modeling and molecular simulations to demonstrate that the curvature of the superheated or supercooled surface depends on the temperature and distances between ice-binding molecules, but not the details of their interactions with ice. We perform simulations of ice pinned with the antifreeze protein TmAFP, polyvinyl alcohol with different degrees of polymerization, and model ice-binding molecules to determine the thermal hystereses on melting and freezing, i.e. the maximum curvature that can be attained before, respectively, ice melts or grows irreversibly over the ice-binding molecules. We find that the thermal hysteresis is controlled by the bulkiness of the ice-binding molecules and their footprint at the ice surface. We elucidate the origin of the asymmetry between freezing and melting hysteresis found in experiments and propose guidelines to design synthetic antifreeze molecules with potent thermal hysteresis activity.

中文翻译：

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什么控制着固定冰面过冷和过热的极限？

适应寒冷的生物产生抗冻蛋白和糖蛋白，以控制冰的生长，融化和重结晶。已经提出这些分子固定晶体表面，产生阻止晶体生长和熔化的曲率。在这里，我们使用热力学建模和分子模拟来证明过热或过冷表面的曲率取决于温度和冰结合分子之间的距离，而不取决于它们与冰的相互作用的细节。我们进行防冻蛋白Tm固定的冰的模拟AFP，具有不同聚合度的聚乙烯醇和模型化冰结合分子，以确定融化和冻结时的热滞后现象，即分别在冰在结合冰分子上不可逆地融化或生长之前可以达到的最大曲率。我们发现，热滞后受冰结合分子的庞大及其在冰表面的足迹的控制。我们阐明了实验中发现的冻结和融化磁滞之间的不对称性，并提出了设计具有有效热磁滞活性的合成防冻分子的指导原则。