Figure 4.

Nuclear Overhauser data recorded for the Aβ peptides. (A) Expanded region of the 2D NOESY spectrum recorded at 900 MHz for the Aβ^1–40 (red) and Aβ^1–42 (black) peptides at 277 K. The cross-peaks correspond to sequential and intraresidue interactions between the ¹H^N and ¹H^α protons. Significant chemical shift differences between Aβ^1–40 and Aβ^1–42 are seen in this region for the intraresidue H^N–H^α(i,i) M35 and sequential H^α–H^N(i,i+1) M35-V36 cross-peaks. (B) Expanded region of the 2D projection from the 3D NOESY-HSQC spectrum recorded at 900 MHz for Aβ^1–40, showing the H^N–H^N region. (C) Ratio between the intraresidue d_aN(i,i) NOE intensity and the sequential H^α–H^N(i–1,i) NOE measured for Aβ^1–40 and reported as a function of residue number. (D) Correlation between the intraresidue d_aN(i,i) NOE intensity and the ¹⁵N transverse relaxation rate measured at a ¹H frequency of 600 MHz.