Fig. 6
DDOX binds to hydrophobic surfaces in α-Syn PFF. (A) Absorbance spectrum of DDOX from supernatants obtained after centrifuging samples incubated either with DDOX or DDOX + α-Syn PFF. The decrease in absorbance, indicating reduced concentration, implies that DDOX bound to and precipitated together with α-Syn PFF. n = 4. (B) Bis-ANS fluorescence signal of α-Syn PFF + DDOX at 1, 50 and 100 µM. The decrease in maximum fluorescence intensity of Bis-ANS (λex = 395 nm) observed at increasing DDOX concentrations highlights a reduction of hydrophobic surfaces in α-Syn fibrils. Bis-ANS alone and α-Syn monomers (α-Synm) are shown as controls. n = 3. (C) Docking simulations of the interaction of DDOX with α-Syn fibrils (PDB ID 2N0A). DDOX is shown in green and α-Syn fibrils are shown in gold. Two putative binding modes to hydrophobic patches are shown. (D-E) The main hydrophobic and polar interactions between DDOX and α-Syn fibrils for both binding modalities are highlighted. Key residues are shown as sticks. Molecular docking simulations were performed using AutoDock Vina 1.1.2. Molecular docking model visualizations, analysis, measurements, and figure generation were performed with Pymol [The PyMOL Molecular Graphics System, Version 1.2r3pre, Schrödinger, LLC.] and ChimeraX version 1.8. Values in (A) and (B) represent the mean of 4 and 3 independent experiments, respectively, and error bars are ± SD.
