Aβ under stress: the effects of acidosis, Cu 2+ -binding, and oxidation on amyloid β-peptide dimers.

In light of the high affinity of Cu2+ for Alzheimer's A(1-42) and its ability to subsequently catalyze the formation of radicals, we examine the effects of Cu2+ binding, A oxidation, and an acidic environment on the conformational dynamics of the smallest A(1-42) oligomer, the A(1-42) dimer. Transition networks calculated from Hamiltonian replica exchange molecular dynamics (H-REMD) simulations reveal that the decreased pH considerably increased the -sheet content, whereas Cu2+ binding increased the exposed hydrophobic surface area, both of which can contribute to an increased oligomerization propensity and toxicity.