脂肪酶定向合成EPA/DHA甘油脂的催化机制和产物构效关系研究

EPA and DHA are important bioactive substances for human growth and metabolism, and have potential applications in food and pharmaceutical industries. EPA/DHA glycerides have higher stability, digestibility and safety compared with other forms of EPA/DHA. Meanwhile, the structure of EPA/DHA glycerides has a significant effect on their nutritional function. So it is valuable to synthesize DHA/EPA glycerides with specific structure and elucidate the structure-activity relationships of the DHA/EPA glycerides in different structure. . In this study, a new lipase, LipLH151, was cloned and expressed from Stenotrophomonas maltophilia in our group. We will study the enzymatic selectivity of LipLH151 and establish catalytic models with high efficiency. Then we will analysis the micro three-dimensional structure of LipLH151 by homology modeling and crystallizing binary complex of enzyme-substrate. Meanwhile, combining molecular docking, dynamic simulation and binding free energy calculation, we will reveal the catalytic mechanism and the binding mechanism of LipLH151 with different substrates in synthesis of different kinds of EPA/DHA glycerides. What’s more, artificial enzymes with improved selectivity will be obtained through the rational design. With the novel artificial enzymes, EPA/DHA glycerides with specific structure would be prepared directionally and efficiently, and their functional activity and structure-activity relationship would also be studied. Based on this research, we will establish the enzymatic technologies for the synthesis of EPA/DHA glycerides with specific structure, and enrich the functional polyunsaturated fatty acid glycerides library and the product functionality information.

EPA和DHA是重要的生理活性物质，在食品领域有着广泛的应用。与其它形式的EPA/DHA相比，EPA/DHA甘油酯具有更高的稳定性、消化利用率和食用安全性，同时EPA/DHA甘油酯的构型对其功能活性有显著影响，因此酶法制备特定构型EPA/DHA甘油酯并阐明其构效关系具有重要意义。本项目以课题组具有良好工作基础的嗜麦芽窄食单胞菌脂肪酶为工具酶，研究其催化选择特性并建立调控模型。同时利用同源建模和酶与酶底二元复合物结晶解析酶的微观结构；结合分子对接、分子动力学分析和结合自由能计算等方法揭示其催化合成不同构型EPA/DHA甘油酯的底物结合机理和催化机制；通过理性设计获得催化选择性提高的人工设计酶；进而实现特定构型EPA/DHA甘油酯的定向制备，并进一步研究其功能活性与构效关系。本研究对于建立特定构型EPA/DHA甘油酯的酶催化制备技术、丰富功能性多不饱和脂肪酸甘油酯库和产物功能信息具有重要意义。

EPA和DHA是重要的生理活性物质，在食品领域有着广泛的应用。与其它形式的EPA/DHA相比，EPA/DHA甘油酯具有更高的稳定性、消化利用率和食用安全性，同时EPA/DHA甘油酯的构型对其功能活性有显著影响，因此酶法制备了特定构型EPA/DHA甘油酯并阐明其构效关系具有重要意义。本项目以课题组具有良好工作基础的嗜麦芽窄食单胞菌脂肪酶为工具酶，研究其催化选择特性并建立了调控模型。同时利用同源建模和酶与酶底二元复合物结晶解析酶的微观结构；结合分子对接、分子动力学分析和结合自由能计算等方法揭示了其催化合成不同构型EPA/DHA甘油酯的底物结合机理和催化机制；通过理性设计获得了催化选择性提高的人工设计酶；进而实现特定构型EPA/DHA甘油酯的定向制备，并进一步研究其功能活性与构效关系。本研究对于建立特定构型EPA/DHA甘油酯的酶催化制备技术、丰富功能性多不饱和脂肪酸甘油酯库和和海洋功能食品的开发具有重要意义。