Weaker N-Terminal Interactions for the Protective over the Causative Aβ Peptide Dimer Mutants.Knowing that abeta amyloid peptide (Aβ42) dimers are the smallest and most abundant neurotoxic oligomers for Alzheimer's disease (AD), we used molecular simulations with advanced sampling methods (replica-exchange) to characterize and compare interactions between the N-termini (residues 1-16) of wild type (WT-WT) and five mutant dimers under constrained and unconstrained conditions. 
replica-exchange