Structure-function relationship in the antifreeze activity of synthetic alanine-lysine antifreeze polypeptides.
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.
Wierzbicki
A
A
Department of Chemistry, University of South Alabama, Mobile, Alabama 36688, USA.
Knight
C A
CA
Rutland
T J
TJ
Muccio
D D
DD
Pybus
B S
BS
Sikes
C S
CS
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
D010455:Peptides; D014867:Water; D008239:Lysine; D000409:Alanine