Ordered surface carbons distinguish antifreeze proteins and their ice-binding regions.
Antifreeze proteins (AFPs) are found in cold-adapted organisms and have the unusual ability to bind to and inhibit the growth of ice crystals. However, the underlying molecular basis of their ice-binding activity is unclear because of the difficulty of studying the AFP-ice interaction directly and the lack of a common motif, domain or fold among different AFPs. We have formulated a generic ice-binding model and incorporated it into a physicochemical pattern-recognition algorithm. It successfully recognizes ice-binding surfaces for a diverse range of AFPs, and clearly discriminates AFPs from other structures in the Protein Data Bank. The algorithm was used to identify a novel AFP from winter rye, and the antifreeze activity of this protein was subsequently confirmed. The presence of a common and distinct physicochemical pattern provides a structural basis for unifying AFPs from fish, insects and plants.