真菌疏水蛋白rHGFI杆状结构自组装与其生物学功能的关系

Based on their immobilization and dispersing activity, the class I hydrophobins are considered as interesting candidates for biological nanometermaterial. However, due to the low solubility of these proteins, the crystal structure can not be obtained, and the relationship of its protein structure and biological function is unclear, so that the determination of condition in the process of drug release and biosensor electrode modification is lack of strong scientific basis..In this project, the recombinant class I hydrophobin HGFI (rHGFI) is employed as the target protein, and the rodlets structure of this protein is chosen as breakthrough. The aim of this study is to explore the formation conditions, structure changes of the class I hydrophobin rodlets structure and the correlation between the rodlets structure formation, changes and the film stability and biological functions, which could be analysed through fluorescence probe technique, circular dichroism spectrum, electron microscope and so on. Meanwhile, we also expect to find the key factors that restricted the rodlets structure formation of the class I hydrophobin and to illuminate the structural changes of monomer intramolecular and intermolecular and their association mechanism. This will reveal the relationship between the hydrophobin rodlets and the structural theory of the membrane stability, molecular mechanism and intermolecular recognition in disperse and immobilized process. This will provide theoretical basis for research and application of hydrophobin used as biological nanometermaterial.

I型真菌疏水蛋白由于其高效的固定化和分散活性，已成为倍受关注的新型生物纳米材料。但由于这类蛋白溶解度低，无法得到晶体结构，导致其发挥生物学功能的分子机制不清楚，使得I型真菌疏水蛋白在应用于药物缓释、生物传感器电极修饰等过程中环境因素的确定缺乏有力科学依据。. 本项目以I型真菌型疏水蛋白rHGFI为研究对象，选择其独特的杆状结构为突破口，拟通过荧光探针标记技术及圆二色谱、X射线光电子能谱和电镜等手段，对I型真菌疏水蛋白杆状结构的形成条件、结构组成变化及其与成膜稳定性和生物学功能之间的关系进行研究。找到制约I型真菌疏水蛋白杆状结构形成的关键因素；阐明杆状结构形成过程中单体分子内部、分子间结构变化以及相互缔合的作用机理，进而揭示I型真菌疏水蛋白杆状结构与其成膜稳定性、发挥分散固定化作用关系的分子机理和分子间识别的结构理论，为更广泛地研究和应用疏水蛋白作为生物纳米材料提供理论依据。

I型真菌疏水蛋白是高等丝状真菌在特定生理时期分泌产生的一类小分子量蛋白质，具有很高的表面活性。但是尤其溶解度小获得晶体难，所以对其结构及由结构决定的成膜性质和吸附能力了解甚少。本项目以I型真菌型疏水蛋白rHGFI为研究对象，研究了其结构的形成、变化及与其性质和功能之间的关系。.实验结果表明： I 型疏水蛋白rHGFI在空气/水界面自组装成杆状结构的过程是疏水作用力和静电力共同作用的结果，pH对rHGFI自组装成杆状结构的临界浓度有很大影响，pH越靠近rHGFI的等电点浓度临界值越小，越远离等电点浓度临界值越大；溶液中不同的溶剂和溶质添加物通过竞争性的降低液体表面张力，从而抑制 rHGFI杆状结构的形成过程； rHGFI 在空气/水界面自组装成杆状结构的过程是一个有序的β-片层结构增加的排列过程，而不是一个进行简单的堆积过程； rHGFI 杆状结构的形成过程不是自发的熵增加过程，是一个需要能量的过程。同时这一过程需要有大量的气泡存在作为界面支持； rHGFI在发挥乳化分散功能的过程中杆状结构的形成不是必要条件，甚至会影响其乳化能力。本项目的实施，为更广泛地研究和应用疏水蛋白作为生物纳米材料提供理论依据。