Kim Jun Soo, Damodaran Srinivasan, Yethiraj Arun
Department of Chemistry, University of Wisconsin, Madison, Wisconsin, 53706, USA.
J Phys Chem A. 2009 Apr 23;113(16):4403-7. doi: 10.1021/jp8110748.
The effect of peptides on the growth of ice crystals are studied using molecular dynamics simulations. The growth of the ice crystal is simulated at a supercooling of 14 K, and the effect of a single tetrapeptide on the growth rate is calculated. For pure ice the simulated crystal grows at a rate comparable to experiment. When a peptide molecule is added near the interface, the growth rate is diminished significantly, by up to a factor of 5 for Gly-Pro-Ala-Gly and a factor of 3 for Gly-Gly-Ala-Gly. The retardation occurs via the binding of the peptide to the ice surface, suppression of ice growth near the binding site, and eventual growth of the crystal around the bound peptide. The peptide with a proline residue is more effective in retarding the crystal growth, and this can be understood from the conformation of the peptide within the frozen ice phase after overgrowth. The simulations suggest that short peptides can be effective antifreeze agents.
使用分子动力学模拟研究了肽对冰晶生长的影响。在14K的过冷度下模拟冰晶的生长，并计算了单个四肽对生长速率的影响。对于纯冰，模拟的晶体生长速率与实验相当。当在界面附近添加肽分子时，生长速率显著降低，甘氨酸-脯氨酸-丙氨酸-甘氨酸降低多达5倍，甘氨酸-甘氨酸-丙氨酸-甘氨酸降低3倍。这种阻滞是通过肽与冰表面的结合、结合位点附近冰生长的抑制以及围绕结合肽的晶体最终生长而发生的。含有脯氨酸残基的肽在阻碍晶体生长方面更有效，这可以从过生长后冷冻冰相中肽的构象来理解。模拟结果表明，短肽可以是有效的抗冻剂。
