Figure 1.

(A) 2D ¹H,¹³C methyl correlation spectra of a 5% GlcRAP and a Leu/Val ¹³CHD₂ sample of α-spectrin SH3 at an external magnetic field of 14.1 T (600 MHz), adjusting the MAS frequency to 50 kHz and the effective sample temperature to 20–25 °C. All samples were prepared in a 100% D₂O buffer (details are given in the Methods part). The ¹H, ¹³C HMQC spectrum of the 5% GlcRAP sample is shown (red) superimposed with the respective spectrum of the Leu/Val sample (blue). The ¹³C line width of the Leu/Val sample amounts to 25 Hz. The ¹H line width for both samples is on the order of ~22–25 Hz. The methyl cross peaks in the ¹³C dimension of the 5% GlcRAP spectrum are split into doublets due to evolution of the ¹J_C,C scalar couplings (except for Met). (B) ¹H,¹³C constant-time HSQC spectrum of the 5% GlcRAP sample using a constant-time delay $T=1/J_{C,C}=\mathrm{28.6}\mathrm{ms}$. The ¹³C line width is ~25 Hz (or ~16 Hz if the indirect evolution period is doubled using mirror-image linear prediction). The apparent ¹³C methyl T₂ time for both samples is roughly around ~30 ms. (C) ¹H,¹³C HMQC spectrum of 5% GlcRAP labelled Aβ_1-40 fibrils, recorded at an external magnetic field of 16.4 T (700 MHz) and a MAS frequency of 18 kHz. The ¹H line width is on the order of ~130 Hz. (D) 1D projection of 2D ¹H,¹³C HMQC spectra of all samples. All pulse sequences are given in Fig. S1. The figure was generated with Adobe Illustrator CS5 V.15.02.