title: Structure-function relationship in the antifreeze activity of synthetic alanine-lysine antifreeze polypeptides.
abstract: Recently antifreeze proteins (AFP) have been the subject of many structure-function relationship studies regarding their antifreeze activity. Attempts have been made to elucidate the structure-function relationship by various amino acid substitutions, but to our knowledge there has been no successful from first principles design of a polypeptide that would bind to designated ice planes along a specific direction. In this paper we show the results of our first attempt on an entirely de novo design of an alanine-lysine-rich antifreeze polypeptide. This 43 residue alanine-lysine peptide exhibits characteristic nonequilibrium freezing point depression and binds to the designated (210) planes of ice along the [122] vector. The structural and thermodynamic properties of this polypeptide were determined using circular dichroism spectroscopy and its nonequilibrium antifreeze properties were investigated using an ice-etching method and nanoliter osmometry.
authors.affiliation: Department of Chemistry, University of South Alabama, Mobile, Alabama 36688, USA.
authors.forename: A
authors.initials: A
authors.lastname: Wierzbicki
authors.forename: C A
authors.initials: CA
authors.lastname: Knight
authors.forename: T J
authors.initials: TJ
authors.lastname: Rutland
authors.forename: D D
authors.initials: DD
authors.lastname: Muccio
authors.forename: B S
authors.initials: BS
authors.lastname: Pybus
authors.forename: C S
authors.initials: CS
authors.lastname: Sikes
mesh_terms: D000409:Alanine / Q000737:chemistry*; D000595:Amino Acid Sequence; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002942:Circular Dichroism; D003460:Crystallization; D005613:Freeze Etching; D005615:Freezing; D008239:Lysine / Q000737:chemistry*; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D010455:Peptides; D014867:Water; D008239:Lysine; D000409:Alanine