9322602 Madura The objective of this proposal is to investigate the binding of Type I antifreeze proteins (AFPs) to ice. The results from the binding study will then be used to develop an improved adsorption- inhibition mechanism. This will be accomplished by applying modern molecular modeling techniques on native AFPs bound to an ice surface and at the ice/water interface. These calculations will be used to study what effect hydrogen bonding, hydrophobic and hydrophilic effects, salt bridges, and electrostatics has on the binding of AFPs to ice. Most important is to understand how these properties contribute to the adsorption-inhibition nature of antifreeze proteins. Initially, a docking program will be used to locate potential binding sites on different ice surfaces. Once potential binding sites have been identified, energy minimizations will be used to determine the binding energy of the AFP bound to the ice surface. Molecular dynamics simulations will then be performed to study the interactions of the antifreeze at the ice/water interface and provide starting configurations for free energy perturbation calculations. The free energy perturbation simulations will be used to quantify the free energy contribution of individual amino acids to binding. Finally, Brownian dynamics simulations will be done to study how electrostatics, between the AFP and ice, effects the translational and orientational steering of an AFP's approach to the ice surface in water. The results from this work will provide both a qualitative and a quantitative molecular description of the properties of AFPs which will be useful to the biologist, chemist, and biochemist in their attempts to "design" better synthetic analogs. These synthetic AFPs can then be used to protect frost sensitive food crops, in food storage, in cryosurgical methods, and in the prevention of frostbite. In summary, the data from this work will have an impact in chemistry, biology, physics, compute r science, and biotechnology. %%% The objective of this proposal is to study the interactions between antifreeze proteins (AFPs) and ice. This will be accomplished by applying modern computational and visualization techniques on native AFPs bound to an ice surface and at the ice/water interface. The results from this work will provide both a qualitative and a quantitative molecular description of the properties of AFPs which will be useful to the biologist, chemist, and biochemist in their attempts to "design" better synthetic analogs. These synthetic AFPs can then be used to protect frost sensitive food crops, in food storage, in cryosurgical methods, in inhibition of gas hydrates in gas wells, in the prevention of ice formation in concrete, and in the prevention of frostbite. In summary, the data from this work will have an impact in chemistry, biology, physics, computer science, engineering, and biotechnology. Other faculty members in the Chemistry Department will be able to use the results from this proposal in their teaching. For example, visualization, in "real time", the motion of a moderately sized peptide at the ice/water. This "movie" will provide a mechanism in which to describe the different molecular interactions taking place, e.g. hydrogen bonding, solute-solvent interactions, salt- bridges and etc. which are usually discussed as abstract concepts in the classroom. ***
