Articles you may be interested inExplicit-water theory for the salt-specific effects and Hofmeister series in protein solutions J. Chem. Phys. 144, 215101 (2016) Ice binding proteins (IBPs) are produced by various cold-adapted organisms to protect their body tissues against freeze damage. First discovered in Antarctic fish living in shallow waters, IBPs were later found in insects, microorganisms, and plants. Despite great structural diversity, all IBPs adhere to growing ice crystals, which is essential for their extensive repertoire of biological functions. Some IBPs maintain liquid inclusions within ice or inhibit recrystallization of ice, while other types suppress freezing by blocking further ice growth. In contrast, ice nucleating proteins stimulate ice nucleation just below 0 C. Despite huge commercial interest and major scientific breakthroughs, the precise working mechanism of IBPs has not yet been unraveled. In this review, the authors outline the state-of-the-art in experimental and theoretical IBP research and discuss future scientific challenges. The interaction of IBPs with ice, water and ions is examined, focusing in particular on ice growth inhibition mechanisms.

The formation of large ice crystals via recrystallization processes in foods and water-based materials often decreases the quality and structural integrity of the materials. Hence, there is a widespread academic and commercial interest in natural and synthetic ice crystal growth modifiers which inhibit the recrystallization of ice. Well-known natural ice crystal growth modifiers are antifreeze proteins (AFPs), which inhibit ice recrystallization by adsorbing on the surface of ice crystals. Reliable quantification of the ice recrystallization inhibition (IRI) efficiency is a long-sought goal. In this work, we describe a simple method to quantitatively evaluate IRI efficiency, based on automated image analysis using the circle Hough transform (CHT) algorithm. It enables robust and high throughput analysis of natural and synthetic ice recrystallization inhibitors. Here we use the method to evaluate the impact of a single point mutation in the ice-binding site of QAE on its IRI activity. We find that the T18N mutant of QAE has virtually the same effective ice recrystallization inhibitory concentration as the wild-type QAE. This is in contrast to thermal hysteresis activity, evaluated by cryoscopy or sonocrystallization, where the mutation greatly decreases the activity.INTRODUCTION A predictive understanding of (re)crystallization processes would allow to create nanomaterials with novel or enhanced physical and chemical properties. 1 For example, aligned porous materials and other complex structured polymer-inorganic composites have been created by directional freezing methods. [2][3][4] Conversely, ice recrystallization can have a major detrimental impact on the quality and performance of many water-based materials such as foods, biological materials, paints. 5-7 The force driving ice recrystallization is a lowering in the free energy of the system by a reduction in crystal/solution interface energy, due to; isomass, accretion and migration. 8, 9 Isomass recrystallization involves the change in internal structure of ice crystals, and a reduction of crystal defects and surface irregularities. Accretive recrystallization describes the fusion of two neighboring ice crystals. The dominant mechanism at high sucrose concentration is migratory recrystallization (i.e., Ostwald ripening), wherein the mean ice crystal size increases while the number of ice crystals decreases, at a constant volume of ice. The inhibitory effect of antifreeze proteins