Molecular Dynamics Simulations of Amyloid-β Protein in KCl Salt Solution

The aggregation of amyloid-β (Aβ) proteins is considered to be the main cause for the development of Alzheimer's disease (AD). The conformational transition from α-helix to β-sheet is the main factor for the occurrence of aggregation of Aβ42 peptide. In order to investigate the effect of KCl salt solution on the conformational change of Aβ42 peptide, we investigate the conformational features of full-length Aβ42 peptide monomer in KCl solution with different concentrations using all-atom molecular dynamics simulations. The results show that the KCl salt solution has a great effect on the conformational stability of the Aβ42 peptide. The Aβ42 peptide conformational stability gradually increased with the increase of KCl concentration. The probability of secondary structure elements of Aβ42 peptide changed, the probability of β-sheet structure formation declined. And the flexibility of residues decreased. On the other hand, the chances of contact among internal residues of Aβ42 peptide become greater because of the addition of KCl, which led to a more compact conformation of Aβ42 peptide. The simulation results provide a feasible idea for an in-depth study of the aggregation mechanism of Aβ42 peptide.