Disaccharide Residues are Required for Native Antifreeze Glycoprotein Activity

Antifreeze glycoproteins (AFGPs) are able to bind ice, halt its growth, and the most potent inhibitors of ice recrystallization known. The structural basis for AFGP’s unique properties remains largely elusive. Here we determined antifreeze activities AFGP variants that constructed by chemically modifying hydroxyl groups disaccharide natural AFGPs. Using nuclear magnetic resonance, two-dimensional infrared spectroscopy, circular dichroism, expected modifications were confirmed as well their effect on AFGPs solution structure. We find presence all hydroxyls disaccharides is a requirement native hysteresis maximal inhibition recrystallization. saccharide apparently important acetyl group galactosamine, ?-linkage between threonine, methyl threonine alanine. conclude use hydrogen-bonding through hydrophobic interactions polypeptide backbone equally in promoting observed These criteria should be considered when designing synthetic mimics.