Recently antifreeze proteins (AFP) have been the subject of many structure-function relationship studiesregarding their antifreeze activity. Attempts have been made to elucidate the structure-function relationshipby various amino acid substitutions, but to our knowledge there has been no successful from first principlesdesign of a polypeptide that would bind to designated ice planes along a specific direction. In this paper weshow the results of our first attempt on an entirely de novo design of an alanine-lysine-rich antifreezepolypeptide. This 43 residue alanine-lysine peptide exhibits characteristic nonequilibrium freezing pointdepression and binds to the designated (2
0) planes of ice along the [122] vector. The structural andthermodynamic properties of this polypeptide were determined using circular dichroism spectroscopy andits nonequilibrium antifreeze properties were investigated using an ice-etching method and nanoliterosmometry.