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Alzheimer Abeta(1-42) monomer adsorbed on the self-assembled monolayers

Qiuming Wang1, Jun Zhao, Xiang Yu

  • 1Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, USA.

Langmuir : the ACS Journal of Surfaces and Colloids
|July 6, 2010
PubMed

Insights

Amyloid-beta (Abeta) aggregation on cell membranes drives Alzheimer's disease neuron death. Molecular simulations reveal Abeta monomers prefer alpha-helical structures on surfaces, influenced by surface chemistry and interactions.

Area of Science:

  • Biophysics
  • Computational Chemistry
  • Neuroscience

Background:

  • Amyloid-beta (Abeta) peptide aggregation on cell membranes is a critical factor in Alzheimer's disease (AD) pathogenesis, leading to neuron cell death.
  • Understanding the initial interactions of Abeta monomers with membrane surfaces is crucial for developing therapeutic strategies against AD.

Purpose of the Study:

  • To investigate the conformational dynamics and adsorption behavior of Abeta monomers on self-assembled monolayer (SAM) surfaces.
  • To compare Abeta structure and adsorption on SAMs with its structure in bulk solution.
  • To elucidate the influence of surface chemistry on Abeta conformation and binding affinity.

Main Methods:

  • Employed molecular docking and molecular dynamics simulations.
  • Studied two distinct Abeta monomer conformations: alpha-helix and beta-hairpin.
  • Utilized four SAM surfaces with varying hydrophobicity and charge distributions.

Main Results:

  • The alpha-helical Abeta monomer exhibited greater structural stability on all tested SAM surfaces compared to the beta-hairpin conformation.
  • Abeta monomer adsorption and stability on SAMs are governed by competitive interactions involving Abeta conformation, SAM surface chemistry, and interfacial water dynamics.
  • The binding affinity order for Abeta with SAMs was determined as COOH-SAM > NH(2)-SAM > CH(3)-SAM > OH-SAM, indicating significant roles for electrostatic and hydrophobic interactions.

Conclusions:

  • Abeta monomers likely adopt alpha-helical or random conformations when interacting with cell membrane-like surfaces.
  • Surface chemistry critically dictates Abeta adsorption and structural stability, with electrostatic and hydrophobic forces playing key roles.
  • This study provides fundamental insights into Abeta-surface interactions relevant to Alzheimer's disease mechanisms.

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