Many amyloid fibrils associated with neurodegenerative diseases consist of an ordered fibril core (FC) and disordered terminal regions (TRs). The former represents a stable scaffold, while the latter is rather active in binding with various partners. Current structural studies mainly focus on the ordered FC since the high flexibility of TRs hinders structural characterization. Here, by combining insensitive nuclei enhanced by polarization transfer-based 1H-detected solid-state NMR and cryo-EM, we explored the intact structure of an α-syn fibril including both FC and TRs and further studied the conformational dynamics of the fibril upon binding to lymphocyte activation gene 3 (LAG3)a cell surface receptor that is involved in α-syn fibril transmission in brains. We found that both the N- and C-TRs of α-syn are disordered in free fibrils featuring similar conformation ensembles as those in soluble monomers. While in the presence of the D1 domain of LAG3 (L3D1), the C-TR directly binds to L3D1, meanwhile the N-TR folds into a β-strand and further integrates with the FC, which leads to alteration of the overall fibril structure and surface property. Our work reveals synergistic conformational transition of the intrinsically disordered TRs of α-syn, which sheds light on mechanistic understanding of the essential role of TRs in regulating the structure and pathology of amyloid fibrils.

The electrochemical behavior of UO 2 F 2 in LiF-NaF-KF (46.5-11.5-42 mol%, FLiNaK) melt on Pt electrode was investigated at 550 • C by cyclic voltammetry (CV) and square wave voltammetry (SWV). UO 2 F 2 was prepared by the reaction of UF 4 powder and oxygen at 650 • C, and ascertained by X-ray diffraction (XRD) and Raman spectroscopy. It was found that the reduction of UO 2 2+ in FLiNaK exhibited two steps both with one exchanged electron: UO 2 2+ + e − → UO 2 + and UO 2 + + e − → UO 2 , with the CV reduction peak at about 2.02 V and 1.49 V (vs. K + /K), respectively. Both of them were reversible and diffusion-controlled. By means of potentiostatic electrolysis, the product of UO 2 was obtained and the separation ratio of uranium from UO 2 F 2 -FLiNaK melt was approximately 54.5% at 550 • C, which were characterized by XRD and the inductively coupled plasma atomic emission spectrometer (ICP-AES).