冰核蛋白中不同结构域对成冰核活性的影响及机制研究

冷冻食品产业方兴未艾，而冰核细菌有催化冰晶形成的特性，其可提高冰晶形成温度，减少冻结时间，并改善冷冻食品质构，具有作为冰核制剂应用于冷冻食品领域的潜力。为了满足冷冻食品对冰核制剂的绿色、高效和安全的要求，需进一步开发无细胞成分的高活性冰核蛋白。然而由于目前对冰核蛋白成冰核活性机制的理解并不十分充分，未有相关商业化蛋白产品。为此本研究拟以冰核蛋白IceE为模型，利用含有不同结构域的冰核蛋白截短体和突变体，通过系列实验探讨冰核蛋白C-末端和重复性R-结构域的长度对蛋白聚合物的形成和蛋白活性的影响，并利用和频振动光谱技术在细胞膜界面上研究不同功能结构域对冰核蛋白周围类冰结构水和有序蛋白结构的影响。同时项目也将研究常见食品模拟体系对冰核蛋白活性的影响及其分子机制。通过项目研究可进一步深入理解冰核蛋白促冰晶形成的分子机制，为高活性冰核蛋白在冷冻食品领域的应用开发提供实验数据和理论支撑。

Frozen food industry is thriving today. Ice nucleation bacteria have the functionality to promote ice formation at relatively high temperature in shorter time, with improved texture for frozen food. For it is demanding to develop ice nucleation additives that are green, safe and robust for food industry upgrading, ice nucleation proteins (INPs), which are its cell free form, could meet the requirements for the nucleation additives in food industry. Thus they have showed potential applications in industry. However, the mechanism of ice nucleation properties of INPs still remain unclear, and they have not been commercialized yet. In our study, ice nucleation protein from Erwinia Herbicola s(Uniprot ID :Ice E) is used as a research model to investigate the effects of repeat domain and C terminal on the overall ice nucleation activities and to understand how they contribute to the formation of aggregates. Ice-like water caused by different truncations and variants of INP at interfaces and the rotations with secondary structure information would be revealed by Sum Frequency Generation Vibrational Spectroscopy (SFG-VS). We would further include common food models in the study to explore their influences on the ice nucleation activities of INP and its reason by SFG and etc. The ultimate goal of our project is to understand the ice nucleation mechanism of INP, and to provide theoretical support for the final applications of highly active INP in frozen food industry.