Table 1.
Aβ turn dynamics and oligomerization propensity
| Peptide | Digestion, % | IT | IR | ΔΔGf | Oligomerization propensity |
|
|---|---|---|---|---|---|---|
| Aβ40 | Aβ42 | |||||
| Flemish (A21G) | 23 | + | + | −0.3 | 6 | 6 |
| Wild type | 27 | +++ | + | 0 | 5 | 5 |
| Dutch (E22Q) | 35 | ++ | + | −0.1 | 4 | 1 |
| Italian (E22K) | 48 | ± | − | 1.2 | 2–3 | 2–3 |
| Iowa (D23N) | 55 | + | − | 0.9 | 2–3 | 2–3 |
| “Arctic 23” (D23G) | 80 | ± | − | 1.9 | ND | ND |
| Arctic (E22G) | 87 | + | − | 2.0 | 1 | 4 |
| “Italian 23” (D23Orn) | 99 | ± | − | 2.6 | ND | ND |
Shown are the final (plateau) trypsin digestion levels, as specified in Fig. 1; the Lys-28HζN TOCSY peak intensity (IT) (±, very weak; +, weak; ++, medium; +++, strong); the Glu-22αH–Gly-29NH, Glu-22αH–Ala-30NH ROESY cross-peak intensities (IR) (+, present; −, absent); the free energies of folding relative to wild type Aβ(21–30) in units of kBT (uncertainty in ΔΔGf values is ≈0.2 kBT); and the oligomerization propensity values for Aβ40 and Aβ42, determined by photoinduced cross-linking of unmodified proteins (36), with the highest propensity being 1.