我国特有天然植物来源甜味化合物“甜味觉”感知的分子机制及其构效关系

甜味觉作为人类5种味觉感知系统之一，由位于口腔味蕾细胞膜上的G蛋白偶联受体-T1R2/T1R3所介导。我国具有丰富的天然植物来源的特有甜味化合物资源，然而，某些甜味物质如何呈现其甜味感觉尤其是“后余甜味”以及其“构效关系”，目前尚不清楚，也限制了对这些甜味物质的开发利用。本研究以我国特有天然甜味化合物罗汉果苷和白云参苷为研究对象，综合运用生物化学、结构生物学、计算生物学、神经生物学等多种研究方法，揭示其在甜味受体上的结合位点与作用方式，及其激活受体的分子机制。在此基础上，阐明它们的甜味度、有效作用浓度范围、构效关系，揭示其“甜味觉”产生的分子机理。本项目研究成果不仅有望阐明我国特有天然甜味化合物“后余甜味”产生的分子机理，还可进一步揭示其结构与功能的关系，并为此类甜味化合物的开发利用提供理论指导。

The sweet taste is one of the five taste senses in human beings, which is mediated by the G protein coupled receptor-T1R2/T1R3 on the membrane of taste buds in mouth. There are plentiful natural sweet taste compounds resources in China. However, how some sweet compounds elicit their sweetness especially “sweet aftertaste” as well as their structure-activity relationship, remain unknown up to now, which limit further applications of these sweeteners. In this research, two sweeteners of characteristic natural sweet compounds in China, mogroside and baiyunoside, will be studied. By use of biochemistry, structural biology, computational biology and neuroscience methods, the binding sites of these sweeteners on the sweet taste receptor T1R2/T1R3, the interaction manner between them and the mechanism of receptor activation, will be illuminated. Furthermore, the sweetness, effective taste threshold and structure-activity relationship of these sweet compounds will be elucidated. These findings can not only reveal the molecular mechanism of “sweet aftertaste” of the characteristic natural sweet compounds in China, but also uncover their structure-function relationship and provide meaningful guidelines for their developments and applications.