Figure 1.

Metal ions specifically bind to the N-terminal part of Aβ and form a compact metal-Aβ complex. (a) ¹H–¹⁵N HSQC spectrum of 75 μM Aβ40 in 10 mM HEPES, pH 7.2, with (violet) and without (black) 100 μM Cu(II) at 281 K.¹ (b–d) Relative ¹H–¹⁵N HSQC signal intensities of Aβ40 in the presence of different concentrations of Cu(II), Zn(II), and Ag(I). Metal ion concentrations were 40 (black-violet), 60 (dark violet), 75 (violet) and 100 μM (light violet) for Cu(II), 20 μM for Zn(II) (blue), and 20 (dark green), 40 (green) and 80 μM (light green) for Ag(I) for 75 to 80 μM Aβ40.¹⁻³ (e) Relative translational diffusion coefficients of Cu(II), Zn(II), and Ag(I) with a global fit to a two-state model, where the diffusion coefficients for the “unfolded” and compact “folded” states are shared fitting parameters.¹ Data were replotted from refs (1−3).