Ice-binding proteins (IBPs) are unique molecules that bind to and are active on the interface between two phases of water: Ice and liquid water. This property allows them to affect ice growth in multiple ways: Shaping ice crystals, suppressing the freezing point, inhibiting recrystallization and promoting nucleation. Advances in the protein's production technologies make these proteins promising agents for medical applications among others.Here, we focus on a special class of IBPs that suppress freezing by causing thermal hysteresis (TH): Antifreeze proteins (AFPs). The kinetic pinning model describes the dynamics of a growing ice face with proteins binding to it, which eventually slow it down to a halt. We use the kinetic pinning model, with some adjustments made, to study the TH dependence on the solution's concentration of AFPs by fitting the model to published experimental data. We find this model describes the activity of (moderate) type III AFPs well, but is inadequate for the (hyperactive) Tenebrio molitor AFPs. We also find the engulfment resistance to be a key parameter, which depends on the protein's size. Finally, we explain intuitively how TH depends on the seeding time of the ice crystal in the protein solution. Using this insight, we explain the discrepancy in TH measurements between different assays. This article is part of the theme issue 'The physics and chemistry of ice: Scaffolding across scales, from the viability of life to the formation of planets'.
|Original language||American English|
|Journal||Philosophical transactions. Series A, Mathematical, physical, and engineering sciences|
|State||Published - 3 Jun 2019|
Bibliographical noteFunding Information:
Data accessibility. This article has no additional data. Authors’ contributions. M.C. performed the data analysis and drafted the manuscript. I.B. conceived of and designed the study. All authors read and approved the manuscript. Competing interests. The authors declare that they have no competing interests. Funding. I.B. acknowledges support from the Israel Science Foundation, grant no. 930/16. M.C. acknowledges support from The Samuel and Lottie Rudin Scholarship Foundation. Acknowledgements. The authors acknowledge helpful discussion with Peter L. Davies and Maya Bar-Dolev.
© 2019 Royal Society Publishing. All rights reserved.
- Antifreeze proteins
- Ice-binding proteins
- Thermal hysteresis