Figure 6. Ligand interaction with fibrillar Aβ₄₂ by saturation transfer difference (STD) NMR (600 MHz).

STD NMR spectra of (a) Verbascoside and (b) VPP at a 250:1 ligand to peptide ratio using pre-assembled Aβ₄₂ fibrils (1 μM). Comparison of the STD signal intensity (red) to the STD reference intensity (black) reflects the relative proximity of the corresponding proton to the Aβ₄₂ fibril. The STD effect calculated from relative intensities was correlated to the structure of Verbascoside (c) and VPP (d) to generate group epitope maps.