Valine substituted winter flounder `antifreeze': preservation of ice growth hysteresis

FEBS Letters

Haymet, A.D.J¹  Knight, Charles A²  Harding, Margaret M³  Ward, Leanne G³ 

[1] Department of Chemistry, University of Houston, Houston, TX 77204-5641, USA;National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307, USA;School of Chemistry F11, University of Sydney, Sydney, NSW 2006, Australia

关键词: Antifreeze;    α-Helical peptide;    Ice growth inhibition;    Threonine residue;    Hysteresis;   

DOI  :  10.1016/S0014-5793(98)00652-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Three mutant polypeptides of the type I 37-residue winter flounder `antifreeze' protein have been synthesized. All four threonine residues in the native peptide were been mutated to serine, valine and glycine respectively and two additional salt bridges were incorporated into the sequences in order to improve aqueous solubility. The peptides were analyzed by nanoliter osmometry, the `ice hemisphere' test, the `crystal habit' test, measurement of ice growth hysteresis and CD spectroscopy. While the valine and serine mutants retain the α-helical structure, only the valine mutant retains `antifreeze' activity similar to that of the native protein. These data show that the threonine hydroxyl groups do not play a crucial role in the accumulation of the native `antifreeze' protein at the ice/water interface and the inhibition of ice growth below the equilibrium melting temperature.

【 授权许可】

Unknown