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

食品中的蛋白质不仅从营养角度来看很重要，而且作为功能性成分也很重要，因为它们能够形成凝胶，稳定乳液，结合水，并作为增稠剂。这些功能特性与蛋白质构象直接相关，但缺乏对复杂食品系统中这些关系的详细了解。在我们的工作中，傅里叶变换红外（FTIR）光谱被用来研究蛋白质构象的变化，可能会发生的条件下，蛋白质暴露在加工和储存过程中，并将这些变化与蛋白质功能的变化。该研究计划的具体方面将进一步推进，包括调查食品蛋白质在高压（UHP），超高温（UHT）和微波处理下的构象变化，这些处理越来越多地用于食品加工。此外，随着最近获得配备焦平面阵列（FPA）检测器的红外显微镜（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值和温度变化，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，一个快速混合器的微流体装置已被设计，并将作为一个多功能的工具，用于监测蛋白质的构象变化与时间分辨率上的亚毫秒的时间尺度。总而言之，这个为期五年的研究计划的基本探索性质适合NSERC Discovery的任务，不仅应该对理解重要食物蛋白质的行为做出实质性贡献，这将有助于食品工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来解决基本的生化意义问题。

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.