Antifreeze protein-induced morphological modification mechanisms linked to ice binding surface

Area of Science:

• Biochemistry
• Materials Science
• Crystallography

Background:

• Antifreeze proteins (AFPs) are crucial for organisms surviving in sub-zero environments.
• Understanding AFP-ice interactions is key to controlling ice formation in various applications.

Purpose of the Study:

• To precisely identify the mechanisms by which insect and fish AFPs modify ice morphology.
• To elucidate the role of the ice-binding surface (IBS) in these distinct modification processes.

Main Methods:

• Analysis of ice-binding surface (IBS) structures of insect AFPs and fish AFPs/antifreeze glycoproteins.
• Comparison of IBS spacing and geometry with primary and secondary ice surfaces.
• Theoretical formulation and experimental validation of AFP-ice interaction models.

Main Results:

• Insect AFPs with 2D IBS cause surface poisoning on primary ice surfaces by matching bonding directions.
• Fish AFPs and glycoproteins with 1D/irregular IBS induce surface reconstruction on secondary ice surfaces by bridging lattice gaps.
• AFP binding adjusts face indices on secondary ice surfaces to maximize protein-substrate interaction.

Conclusions:

• Distinct IBS structures dictate whether AFPs poison or reconstruct ice surfaces.
• AFP mechanisms are tailored to specific ice surface types (primary vs. secondary) and their crystallographic features.
• This study resolves previously unexplained phenomena in AFP-ice interactions and provides a unified theoretical framework.