纤维素酶能将纤维素水解成葡萄糖，在生物质能源的开发利用中具有巨大的应用潜力。然而它催化效率低、热稳定性差等缺点成为制约其应用的瓶颈。在能源危机日益严重的今天，改良纤维素酶催化活性、提高其热稳定性的研究受到广泛关注。最近，具有85°C最适反应温度的纤维素酶TmCel12A晶体结构的获得和具有进一步提高其耐超高温特性的Y61G突变体的发现为研究TmCel12A耐超高温特性的机理提供了可靠的实验基础。本项目拟以此为突破口，在前期工作基础上，利用理论与实验相结合的方法综合运用分子动力学模拟、量子力学-分子力学多尺度模型、自由能计算以及酶活性测定、酶反应动力学参数测定等方法，从酶自身热稳定性、酶-底物复合体热稳定性、复合体形成和产物释放、以及热稳定性与催化活性相关性等四个方面全方位研究TmCel12A耐超高温特性的机理，为设计改良其它纤维素酶及类似水解酶提供可靠的理论基础，推动生物质能源的开发利用。

Cellulase, an enzyme that hydrolyses cellulose into glucoses, has great potential for renewable energy, such as biomass energy. However, the low efficiency, poor thermal stability and the end-product inhibition effect become the bottleneck for the application of cellulases. Today, with energy crisis becoming more and more severe, researches that focus on improving the activities and thermostabilities of cellulases attract more and more attention. Recently, the crystal structure of a cellulase, TmCel12A, with an optimum temperature of 85°C has been solved and the newly found gain-of-function mutation, Y61G, has been proved to improve both the hyperthermal stability and reaction activity of TmCel12A. These experimental achievements provide a solid base for further study of the hyperthermal nature of TmCel12A. Based on our research experience and the preliminary results, we proposed to clarify the mechanism of the hyperthermal stability of TmCel12A from the aspects of the enzyme thermal stability, the thermal stability of enzyme-substrate complex, the formation of the enzyme-substrate complex, the release of the products and relationship between the thermal stability and the activities of TmCel12A. A combination of both theoretical and experimental approach including molecular dynamics simulation, quantum mechanics, QM/MM, free energy calculation, enzyme activity determination, and enzyme dynamics profile measurement will be applied. It will provide a theoretical guide for the improvement modification of not only cellulases but also other hydrolysis enzymes, therefore of great help in promoting the massively application of biomass energies.