基于嵌段聚合物自组装复合材料的超分子响应性仿生硒酶构筑及催化机制研究

The simulation of biomolecule with magical functions in nature can not only provide an important method for the recognition of nature and the designing of new biomimetic materials, but also function as important source of original innovation in the field of biological chemistry. The catalytic process of natural enzyme endowed with the conformation changes for substrate binding using the induced-fit catalytic process. Using such process as similation object, the construction of biomimetic enzyme with the property of intelligent response has become an important scientific problem. Therefore, this project is intented to propose the simulation of the biological enzyme functioning as a guide and the construction of supramolecular responsive biomimetic selenium enzymes as targets. To establish a new method for the preparation of block polymer composite materials with the property of supramolecular response. And to explore the new strategy for intelligent regulation of the matching and coordination of catalytic elements.Furthermore, the charactization techniques of UV, fluorescence, NMR, SEM and TEM were empolyed to explore these basic scientific problems, such as the assembled behavior of self-assembled composite material, the supramolecular response mechanism of biomimetic selenium enzyme, the intelligent regulation of the matching and coordination of catalytic element, etc. And this project is aimed to establish the construction strategy of block polymer composite material with the property of supramolecular response, to clarify the response mechanism of self-assembled structure of composite material. Moreover, this project is aimed to optimize the structure of biomimetic selenium enzyme, and to reveal the catalytic property of it. Significantly, the mechanism for intelligent regulation of the matching and coordination of catalytic element caused by supramolecular response would be explored. The successfully research of this project in future may provide the theoretical basis for the construction of efficient biomimetic selenium enzyme with induced-fit catalytic property similar to natural enzyme and provide the basement for the development of a new intelligent antioxidant drug.

模拟自然界中生物分子神奇的功能不仅是对自然再认识和创造新型仿生材料的重要手段，而且还成为生物化学领域原始创新的重要源头。天然酶存在构象变化对底物诱导契合催化的过程，以此为模拟对象构筑智能仿生酶已成为重要科学问题。本课题提出以模拟生物酶功能为导向，以构筑超分子响应性仿生硒酶为目标，拟制备新型超分子响应嵌段聚合物复合材料，探索对仿生硒酶的催化基元匹配和协同作用进行精确智能调控的新策略。拟采用紫外、荧光、核磁、SEM、TEM等测试作为分析手段，研究复合材料的组装行为、仿生硒酶的超分子响应机制、仿生硒酶催化行为的精确智能调控机制等基础科学问题。建立超分子响应复合材料的制备方法，阐明复合材料组装结构的超分子响应机制；完成仿生硒酶的结构优化，揭示其催化本质；明确对仿生硒酶的催化基元匹配和协同作用精确智能调控的机制，为构筑与天然酶诱导契合过程类似的高效智能仿生硒酶奠定基础，为研究新型抗氧化药物提供依据。

结合生物和化学技术，模拟自然界中天然酶分子的神奇功能，是生物化学领域原始创新的重要源头。模拟天然酶构象变化对底物诱导契合的催化过程，构筑智能仿生酶是该领域的重要科学问题。本课题以模拟谷胱甘肽过氧化物酶为导向，以构筑超分子响应性仿生硒酶为目标，制备了新型超分子响应仿生硒酶，并研究了该仿生硒酶催化活性的精确调控机制。实验结果表明，改变聚合物结构制备的功能化客体嵌段聚合物均可以在一定条件下形成70-900纳米不等的球状实心胶束结构。通过对比不同比例客体嵌段聚合物制备的仿生硒酶的催化活力，选定萘酚单体、丙烯酰胺单体、含碲小分子单体比例为1:10:0.5时制备的仿生硒酶为优化的客体嵌段聚合物骨架，该仿生硒酶的催化活力为2.93 µMmin-1。利用共混技术，改变修饰有识别位点和催化中心的聚合物比例对仿生硒酶的结构进一步优化表明，当修饰有识别位点的聚合物中精氨酸与修饰有催化中心的聚合物比例是0.6:1时，仿生硒酶表现出最佳催化活力6.55 µMmin-1。以枯烯过氧化氢和3-羧基-4硝基苯硫酚为底物时，该仿生硒酶的表观动力学常数如下：Vmax=31.15 µMmin–1, kcatapp = 31.15 min–1, KmCUOOH = 2361 µM, kcatapp/Km CUOOH = 1.32×104 M–1min–1。仿生硒酶骨架中疏水微环境和识别位点的存在能显著增仿生硒酶对底物的识别能力，是维持高催化活性的关键因素。利用核磁、荧光、紫外、纳米粒度仪等研究表明，随着不同比例环糊精或金刚酸钠的加入，聚合物的自组装结构表现出可逆变化规律，对应仿生硒酶的催化活力表现出典型的可逆响应性催化活力。考虑到该超分子响应过程中只有环糊精和金刚酸钠加入到复合物体系中，因此，复合物变化可能是由于金刚酸钠与环糊精空腔的复合作用更强、将萘酚部位挤出环糊精疏水空腔导致的。此外，仿生硒酶的催化活力表现出较好的可重复性，间接证明了仿生硒酶的自组装结构在酶活测试系统中比较稳定。本研究制备了系列催化活力可调控的仿生硒酶，对于制备其他超分子响应材料同样具有借鉴意义，在智能材料领域具有广阔的应用前景。