Investigations of nonequilibrium antifreeze activity of synthetic antifreeze polypeptides

CHED 996

Camden N. Henderson, henderso@jaguar1.usouthal.edu1, Charles A. Knight, knightc@ucar.edu2, and Andrzej Wierzbicki, awierzbi@jaguar1.usouthal.edu1. (1) Department of Chemistry, University of South Alabama, Mobile, AL 36688, (2) National Center for Atmospheric Research, Boulder, CO 80307
We have studied the role of both polar and non-polar residues in non-equilibrium antifreeze activity in a series of ten de-novo designed synthetic α-helical antifreeze polypeptides. The sequences of these alanine/lysine-based antifreeze polypeptides were derived using methods of computational chemistry. Site-specific modifications of selected amino acids were studied for their impact on the non-equilibrium antifreeze activities of these polypeptides using ice etching, nanoliter osmometry, circular dichroism spectroscopy, and mass spectroscopy. Based on these studies, the role of both polar and non-polar residues in non-equilibrium antifreeze activity at the water/ice interface will be discussed.