Investigations of protein conformation, interactions and dynamics by Fourier transform infrared spectroscopy

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Proteins in foods are important not only from a nutritional perspective but also as functional ingredients because of their ability to form gels, stabilize emulsions, bind water, and act as thickening agents. These functional properties are directly related to protein conformation, but a detailed understanding of these relationships in complex food systems is lacking. In our work, Fourier transform infrared (FTIR) spectroscopy is being employed to study changes in protein conformation that may occur under the conditions to which proteins are exposed during processing and storage and to relate these changes to changes in protein functionality. Specific aspects of this research program that will be further advanced include the investigation of conformational changes of food proteins subjected to high pressure (UHP), ultrahigh temperature (UHT), and microwave treatments, which are increasingly being employed in food processing. In addition, with the recent acquisition of an IR microscope equipped with a focal-plane-array (FPA) detector (courtesy of an NSERC Research Tools and Instruments Grant), the applicant will develop new FTIR methodologies for time-resolved studies of protein dynamics, protein-protein interactions, and the responses of proteins to pH and temperature changes, metal ions, sugars, solvents, denaturants, and ligands. For this purpose, a rapid-mixer microfluidic device has been designed and will serve as a versatile tool for monitoring conformational changes in proteins with a time resolution on the submillisecond time scale. Altogether, the basic exploratory nature of this five-year research program suits the NSERC Discovery mandate and should not only contribute substantively to the understanding of the behavior of important food proteins that will assist the food industry in making more effective use of these proteins but will also provide us and other researchers with new tools to address questions of fundamental biochemical significance.