Computer Simulations Reveal How Anti-Freeze Proteins Work

Antifreeze proteins are found in fish, moths, plants, and bacteria.

The Science

Atomistic molecular dynamics simulations are used to investigate the mechanism by which the antifreeze protein from the spruce budworm, Choristoneura fumiferana, binds to ice. Comparison of structural and dynamic properties of the water around the three faces of the triangular prism-shaped protein in aqueous solution reveals that at low temperature the water structure is ordered and the dynamics slowed down around the ice-binding face of the protein, with a disordering effect observed around the other two faces. These results suggest a dual role for the solvation water around the protein.

Summary

Research lead by Jeremy Smith of Oak Ridge National Laboratory (ORNL) has yielded new insight into the mechanism of how anti-freeze proteins, found in a wide range of organisms, prevent ice formation.  Utilizing the high performance computational resources at ORNL, the molecular dynamics simulations reveal that at lower temperatures the anti-freeze protein serves a dual purpose: preconfiguring the water to ease ice binding to one face of the protein while disordering the water on the other faces to prevent ice propagation.  ORNL researchers term the preconfiguration effect “pre-ordering-binding” and suggest that the mechanism may be generally applicable to processes occurring at disordered or amorphous surfaces.  A similar simulation approach is planned to examine water structure in lignocellulosic biomass, as similar hydration effects may form a barrier to cellulosic ethanol production.

Principal Investigator

Jeremy Smith
Oak Ridge National Laboratory

Funding

This work is sponsored in part by DOE’s Office of Science.

References

Smith, J., and D. R. Nutt. 2008. “Dual Function of the Hydration Layer around an Antifreeze Protein Revealed by Atomistic Molecular Dynamics Simulations,” Journal of American Chemistry 130(39), 13066–73. DOI:10.1021/ja8034027.