Tetrahedral linkage as an intrinsic measure of glycan antifreeze behavior

Abstract

Antifreeze materials prevent ice-formation by disrupting the ice-formation by binding to certain ice-planes. Cellulose, the most abundant biopolymer, has shown the ability to bind to ice-planes but the exact mechanism of this binding is far from being understood. Molecular dynamics simulations are used to investigate the hydration water of chains of cellulose-type glycans and its significance in the expression of the antifreeze behavior of sugar-derivatives found in some antifreeze materials. We find that glycans are able to prevent water from freezing near its surface by preventing their rearrangement to achieve a highly tetrahedral structure at temperatures well-below the freezing point of water. This validates our hypothesis on the role of tetrahedral coordination based on previous $\textit{ab initio}$ calculations that demonstrated cellulose prefers to bind to ice basal and prismatic planes using a tetrahedral geometry. Our findings suggest that the tetrahedral ordering of water around glycans is the key to understanding and designing cellulose-based antifreeze materials.