Figure 6
From: RNA recognition motifs of disease-linked RNA-binding proteins contribute to amyloid formation
RRM and β peptide fibrils are amyloids of parallel β-sheets based on Fourier transform infrared (FTIR) spectroscopy. The fibrillation properties of FUS RRM, TDP-43 RRM1 and their β2 peptides were analyzed by attenuated total reflection-Fourier transform infrared (ATR-FTIR). ATR-FTIR spectra in the amide I region (1600 to 1700 cm−1) are shown in the left column, and the second derivative ATR-FTIR spectra are displayed in the right column. In these ATR-FTIR spectra, the characteristic shift in β-sheet absorbance at 1630–1640 cm−1 for fresh protein/peptide (in black) to 1620–1630 cm−1 in amyloid fibrils (in red) represents planer extended β-sheet assembly. In the second derivative ATR-FTIR spectra, none of the fibril spectra exhibit a high frequency peak at 1685–1695 cm−1, suggesting the presence of amyloid structures consisting of parallel β-sheets.
