Fig. 4: MAS ssNMR spectra of U−¹³C, ¹⁵N-labeled Q32-HttEx1 fibrils.

a 1D ¹³C CP spectra of fibrils formed at room temperature without curcumin (green), and b with curcumin (at the protein: curcumin ratio of 1:0.33) (black). The spinning frequency was 10 kHz. c 2D ¹³C −¹³C DARR spectrum for U−¹³C, ¹⁵N Q32-HttEx1 fibrils obtained at 13 kHz MAS and 25 ms of DARR mixing. d 2D ¹³C −¹³C DARR spectrum for U−¹³C, ¹⁵N Q32-HttEx1fibrils prepared in presence of curcumin (1:0.33) obtained at 13 kHz MAS and 25 ms of DARR mixing. e Zoomed-in overlay of 1D spectral regions showing Gln Cα peaks (middle) and Pro peaks, from spectra a, b. The NMR measurements were performed at 275 K on a 600 MHz spectrometer.