A Diminished Role for Hydrogen Bonds in Antifreeze Protein Binding to Ice

Citations Over TimeTop 10% of 1997 papers

Abstract

The most abundant isoform (HPLC-6) of type I antifreeze protein (AFP1) in winter flounder is a 37-amino-acid-long, alanine-rich, alpha-helical peptide, containing four Thr spaced 11 amino acids apart. It is generally assumed that HPLC-6 binds ice through a hydrogen-bonding match between the Thr and neighboring Asx residues to oxygens atoms on the {2021} plane of the ice lattice. The result is a lowering of the nonequilibrium freezing point below the melting point (thermal hysteresis). HPLC-6, and two variants in which the central two Thr were replaced with either Ser or Val, were synthesized. The Ser variant was virtually inactive, while only a minor loss of activity was observed in the Val variant. CD, ultracentrifugation, and NMR studies indicated no significant structural changes or aggregation of the variants compared to HPLC-6. These results call into question the role of hydrogen bonds and suggest a much more significant role for entropic effects and van der Waals interactions in binding AFP to ice.

Related Papers

• → Salt-induced enhancement of antifreeze protein activity: A salting-out effect(2008)58 cited
• → Aggregation of Antifreeze Protein and Impact on Antifreeze Activity(2006)29 cited
• → Modelling of short synthetic antifreeze peptides: Insights into ice-pinning mechanism(2020)18 cited
• → Determination of the Minimal Sequence Required for Antifreeze Activity of Type I Antifreeze Protein (AFP 37)(2010)3 cited