無穩定構型蛋白質之摺疊、聚集與分子間交互作用

Abstract

無穩定構型蛋白質(Intrinsically disordered protein)為蛋白質交互作用網絡之核心。然 而其穩定予否則端賴其是否摺疊正確。蛋白質摺疊似一階態轉變(first order-like state transition)模型，為適切表達蛋白質摺疊整體反應之模型。然而intrinsically disordered protein 之摺疊反應是否會依循蛋白質摺疊似一階態轉變模型則為本計畫所擬探討之重 點。此外透過量測intrinsically disordered protein 之Raman 與螢光光譜於摺疊中間體之 變化解析，將可找出此類蛋白質摺疊穩定核心。並藉由不同摺疊路徑之熱反應與光譜 特性分析驗證其摺疊反應是否依循蛋白質摺疊似一階態轉變模型。並從而確認其摺疊 態轉變區間與臨界邊界(critical boundary)之主要影響因子。進一步驗證本質非穩定構型 蛋白質之聚集沉澱符合摺疊與擴散速率限制聚集(diffusion limited aggregation)相拮抗 之模型。此外本計劃將利用介電泳驅動分子自組裝法，結合特徵奈米結構矽基材，以 研究此類本質非穩定構型蛋白質自我組裝之特性。並藉由原子力顯微鏡與低溫穿透式 電子顯微鏡分析蛋白質聚集與奈米跼限環境下分子自組裝結構之特性。進一步運用光 學與單分子操作分析法，解析此類本質非穩定構型蛋白質與蛋白質loop 區域誘導形變 產生分子交互作用之反應構型轉變。

Intrinsically disordered protein plays a vital role in the networks of protein-protein interactions. However, their stabilities rely on the process of folding. The first order-like state transition model is the proper model to describe the global reaction of protein folding. However, the folding reaction of intrinsically disordered protein remains unknown. Therefore, one of the aims of this project is focusing on the mechanisms study of intrinsically disordered proteins folding and their interactions. Meanwhile, the “first order-like state transition model” will be examined in this project. By using Raman and fluorescence spectroscopy analysis of their folding intermediates, the folding cores of intrinsically disordered protein can be revealed. Meanwhile, the major affecting factors of folding transition region/boundary can be determined by systematically folding studies. These affecting factors may help us to reveal the protein aggregation mechanism. Meanwhile, we will test the competitive model of protein folding and diffusion limited aggregation in this project. In order to reveal the self-assembly mechanism of intrinsically disordered protein, in this project, we will use the molecular dielectrophoresis driven self-assembly method, which developed my laboratory, and make the protein aggregated in the nano-pattern of silicon substrates. Furthermore, the conformation of aggregated protein will be revealed by atomic force microsopy and cryo-transmitted electron microscopy. Meanwhile, the dynamics of this protein aggregation and conformation transition of the loop region during protein-protein interactions can be revealed by optical combining single molecular manipulation methods which development by my laboratory.