Biophysics Department, Siberian Federal University, Svobodny 79, Krasnoyarsk, Russia, 660041.
Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Puschino, Russia.
Protein J. 2022 Apr;41(2):304-314. doi: 10.1007/s10930-022-10049-6. Epub 2022 Apr 2.
Ice-binding proteins are expressed in the cells of some cold adapted organisms, helping them to survive at extremely low temperatures. One of the problems in studying such proteins is the difficulty of their isolation and purification. For example, eight cysteine residues in the cfAF (antifreeze protein from the eastern spruce budworm Choristoneura fumiferana) form intermolecular bridges during the overexpression of this protein. This impedes the process of the protein purification dramatically. To overcome this issue, in this work, we designed a mutant form of the ice-binding protein cfAFP, which is much easier to isolate that the wild-type protein. The mutant form named mIBP83 did not lose the ability to bind to ice surface. Besides, observation of the processes of freezing and melting of ice in the presence of mIBP83 showed that this protein affects the process of ice melting, increasing its melting temperature, and does not decrease the water freezing temperature.
冰结合蛋白在一些适应寒冷的生物体的细胞中表达，帮助它们在极低的温度下生存。研究这类蛋白质的一个问题是其分离和纯化的难度。例如，在该蛋白的过表达过程中，cfAF（来自东方云杉卷叶蛾 Choristoneura fumiferana 的抗冻蛋白）中的 8 个半胱氨酸残基形成分子间桥。这极大地阻碍了蛋白质纯化的过程。为了克服这个问题，在这项工作中，我们设计了一种 cfAFP 冰结合蛋白的突变体形式，它比野生型蛋白更容易分离。这种名为 mIBP83 的突变体形式并没有丧失与冰表面结合的能力。此外，观察 mIBP83 存在下冰的冻结和融化过程表明，该蛋白影响冰融化的过程，提高了冰的融化温度，而不会降低水的冻结温度。
