Unveiling the Interplay between Dopamine-like Molecules and Β-Amyloid Peptide: A Combined Molecular Dynamic and DFT Approach.

Aims: This study aims explore the impact of catechol, dopamine, and L-DOPA on the stability and toxicity of β-amyloid peptides, which play a key role in the neurodegenerative process of Alzheimer's disease, to assess their potential as therapeutic agents.

Background: Alzheimer's disease is marked by the aggregation of β-amyloid peptides, which contribute to neurodegeneration. Exploring how various compounds interact with β-amyloid peptides can offer valuable insights into potential therapeutic strategies.

Objective: The objective of this research is to explore the interaction mechanisms of catechol, dopamine, and L-DOPA with β-amyloid peptides and assess their impact on peptide stability and aggregation.

Method: This study employs molecular dynamics simulations combined with density functional theory to investigate the interactions between β-amyloid and the three compounds. It evaluates changes in peptide stability and salt bridge lengths and performs electronic structure analyses using the Electron Localization Function (ELF) and Harmonic Oscillator Model of Aromaticity (HOMA).

Results: The findings reveal that β-amyloid stability decreases significantly when interacting with dopamine and L-DOPA compared to catechol. All three compounds inhibit β-amyloid, with dopamine and L-DOPA showing stronger effects. Catechol primarily interacts through hydrophobic interactions, while dopamine and L-DOPA also form hydrogen bonds with β-amyloid. Electronic structure analysis shows catechol has higher electron localization and anti-aromatic character, affecting its interactions differently than dopamine and L-DOPA. A decrease in the HOMO-LUMO gap from catechol to L-DOPA to dopamine indicates increasing reactivity towards β-amyloid.

Conclusion: Dopamine and L-DOPA more effectively disrupt β-amyloid aggregation than catechol, likely due to additional hydrogen bonding and increased electronic reactivity. These insights are crucial for developing therapeutic strategies targeting β-amyloid aggregation in Alzheimer's disease, emphasizing the importance of molecular interactions in modulating peptide stability and toxicity. The study also provides a comparative analysis of the electronic properties and interaction dynamics of the compounds, which can guide future research in the design of β-amyloid inhibitors. The utilization of advanced simulation techniques underscores the potential for computational methods in understanding complex biological interactions and developing novel therapeutic agents. Furthermore, the insights into the differential effects of hydrophobic interactions versus hydrogen bonding offer valuable information for the synthesis of new compounds aimed at mitigating β-amyloid toxicity.