ATP Controls the Aggregation of Aβ16-22 Peptides.

The oligomerization of Aβ16-22 peptide, which is the hydrophobic core region of full-length Aβ1-42, causes Alzheimer's disease (AD). This progressive neurodegenerative disease affects over 44 million people worldwide. However, very few synthesized drug molecules are available to inhibit the aggregation of Aβ. Recently, experimental studies have shown that the biological ATP molecule prevents Aβ fibrillation at the millimolar scale; however, the significance of ATP molecules on Aβ fibrillation and the mechanism behind it remain elusive. We have carried out a total of 7.5 μs extensive all-atom molecular dynamics and 8.82 μs of umbrella sampling in explicit water using AMBER14SB, AMBER99SB-ILDN, and AMBER-FB15 force fields for Aβ16-22 peptide, to investigate the role of ATP on the disruption of Aβ16-22 prefibrils. From various analyses, such as secondary structure analysis, residue-wise contact map, SASA, and interaction energies, we have observed that, in the presence of ATP, the aggregation of Aβ16-22 peptide is very unfavorable. Moreover, the biological molecule ATP interacts with the Aβ16-22 peptide via hydrogen bonding, π-π stacking, and NH-π interactions which, ultimately, prevent the aggregation of Aβ16-22 peptide. Hence, we assume that the deficiency of ATP may cause Alzheimer's disease (AD).