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

食物中的蛋白质不仅从营养角度来看很重要，而且作为功能成分也很重要，因为它们能够形成凝胶，稳定乳状液，结合水分，并充当增稠剂。这些功能特性与蛋白质构象直接相关，但缺乏对复杂食物系统中这些关系的详细了解。在我们的工作中，傅立叶变换红外光谱(FTIR)被用来研究蛋白质在加工和储存过程中暴露于各种条件下可能发生的构象变化，并将这些变化与蛋白质功能的变化联系起来。这项研究计划将进一步推进的具体方面包括研究食品蛋白质在高压(UHP)、超高温(UHT)和微波处理下的构象变化，这些都越来越多地被用于食品加工。此外，随着最近购买了配备焦平面阵列(FPA)探测器的红外显微镜(由NSERC研究工具和仪器资助)，申请人将开发新的FTIR方法，用于蛋白质动力学、蛋白质-蛋白质相互作用以及蛋白质对pH和温度变化、金属离子、糖、溶剂、变性剂和配体的响应的时间分辨研究。为此，已经设计了一种快速混合器微流控装置，它将成为监测蛋白质构象变化的通用工具，时间分辨率在亚毫秒级。总之，这项为期五年的研究计划的基本探索性性质符合NSERC发现任务，不仅应该有助于理解重要食品蛋白质的行为，从而帮助食品行业更有效地利用这些蛋白质，而且还将为我们和其他研究人员提供新的工具，以解决具有基本生物化学意义的问题。

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.