Identifying Ice-Philic Protein Patches to Inform the Ice-Binding Sites of Antifreeze Proteins

Abstract

Antifreeze proteins (AFPs) inhibit ice growth and recrystallization by binding to ice crystals via specific regions on their surface, known as ice-binding sites (IBS). Although the IBS of certain AFPs display regularly spaced threonine residues that are matched well with the molecular spacings in ice crystals, the IBS of other AFPs lack such structural signatures, making it challenging to identify them. To address this challenge, we introduce a computational framework that systematically promotes ice formation in the AFP hydration shell. We find that ice-philic AFP regions, which form ice in their vicinity most readily, exhibit strong correspondence with the experimentally determined IBS. Importantly, such correspondence is observed across a diverse set of AFPs, including those with and without a regular array of threonines. We hope that our framework will expedite the identification of ice-binding sites of newly discovered or designed AFPs.