Alternative Assembly of α-Synuclein Leading to Protein Film Formation and Its Application for Developing Polydiacetylene-Based Sensing Materials

Understanding the self-assembly process of amyloidogenic protein is valuable not only to find its pathological implication but also to prepare protein-based biomaterials. α-Synuclein (αS), a pathological component of Parkinson's disease, producing one-dimensional (1D) amyloid fibrils, has been employed to generate two-dimensional (2D) protein films by encouraging an alternative self-assembly process. At a high temperature of 50 °C, αS molecules self-assembled into 2D films instead of 1D amyloid fibrils, whereas the fibrils were the major product at 37 °C. Based on circular dichroism and Fourier transform infrared spectroscopy analyses, the film was produced via a structural transition from the initial random to still undefined but mostly the turn or loop structure, which was distinctive from the β-sheet formation observed with the amyloid fibrils. The αS 2D film was also routinely prepar…