Modelling of short synthetic antifreeze peptides: Insights into ice-pinning mechanism

Organisms living in icy environments produce antifreeze proteins to control ice growth and recrystallization. It has been proposed that these molecules pin the surface of ice crystals, thus inducing the formation of a curved surface that arrests crystal growth. Such proteins are very appealing for many potential applications in food industry, material science and cryoconservation of organs and tissues. Unfortunately, their structural complexity has seriously hampered their practical use, while efficient and accessible synthetic analogues are highly desirable. In this paper, we used molecular dynamics based techniques to model the interaction of three short antifreeze synthetic peptides with an ice surface. The employed protocols succeeded in reproducing the ice pinning action of antifreeze peptides and the consequent ice growth arrest, as well as in distinguishing between antifreeze and control peptides, for which no such effect was observed. Principal components analysis of peptides trajectories in different simulation settings permitted to highlight the main structural features associated to antifreeze activity. Modeling results are highly correlated with experimentally measured properties, and insights on ice-peptide interactions and on conformational patterns favoring antifreeze activity will prompt the design of new and improved antifreeze peptides.