Biophysical Characterization of α-Synuclein and Rotenone Interaction

Abstract

Previous studies revealed that pesticides interact with α-synuclein and accelerate the rate of fibrillation. These results are consistent with the prevailing hypothesis that the direct interaction of α-synuclein with pesticides is one of many suspected factors leading to α-synuclein fibrillation and ultimately to Parkinson’s disease. In this study, the biophysical properties and fibrillation kinetics of α-synuclein in the presence of rotenone were investigated and, more specifically, the effects of rotenone on the early-stage misfolded forms of α-synuclein were considered. The thioflavine T (ThT) fluorescence assay studies provide evidence that early-phase misfolded α-synuclein forms are affected by rotenone and that the fibrillation process is accelerated. Further characterization by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) shows that rotenone increases the amount of ordered secondary structure in this intrinsically disordered protein. Morphological characterization by transmission electron microscopy (TEM) and atomic force microscopy (AFM) provide visualization of the differences in the aggregated α-synuclein species developing during the early kinetics of the fibrillation process in the absence and presence of rotenone. We believe that these data provide useful information for a better understanding of the molecular basis of rotenone-induced misfolding and aggregation of α-synuclein.

Drug and dye binding induced folding of the intrinsically disordered antimicrobial peptide CM15

“…It is to be noted that closely resembling CD spectroscopic changes were witnessed upon titration of the natively unfolded a-synuclein with DDT. 37 In parallel with the increasing concentration of the pesticide, the single negative CD band lost intensity which was considered as the sign of a disordered-to-misfolded conformational shi of the protein.…”

Alpha-Synuclein Fibrils Interact with Dopamine Reducing its Cytotoxicity on PC12 Cells

“…Amide I is important region for research about secondary structure of protein that provides appropriate data concerning about interaction of small molecules with proteins [32]. Figure 6b indicates the second derivative of FTIR absorbance related to the amide I region in fibrillar a-SYN associated with strong peaks at 1624 and 1692 wavenumbers as characteristics of fibrils structures.…”

Immobilization approaches can affect protein dynamics: a surface-enhanced infrared spectroscopic study on lipid–protein interactions

“…Thus our ATR experiments of the supernatant proved that αS in solution performs conformational changes, with and without membrane interactions, in agreement with several other studies. 8,9,14,44,45,[47][48][49][50] In contrast, the immobilization of αS seems to prevent conformational dynamics. Reduced biological activity of covalently bound αS due to surface confinement was reported before.…”