Preordering of water is not needed for ice recognition by hyperactive antifreeze proteins

AFP recognizes and binds ice. We find that water at the IBS of the antifreeze protein in solution does not acquire ice-like or anchored clathrate-like order. Ice recognition occurs by slow diffusion of the protein to achieve the proper orientation with respect to the ice surface, followed by fast collective organization of the hydration water at the IBS to form an anchored clathrate motif that latches the protein to the ice surface. The simulations suggest that anchored clathrate order could develop on the large ice-binding surfaces of aggregates of ice-nucleating proteins (INP). We compute the infrared and Raman spectra of water in the anchored clathrate motif. The signatures of the OH stretch of water in the anchored clathrate motif can be distinguished from those of bulk liquid in the Raman spectra, but not in the infrared spectra. We thus suggest that Raman spectroscopy may be used to probe the anchored clathrate order at the ice-binding surface of INP aggregates.