Chemical and Biomolecular Engineering Faculty Research

Title

Alzheimer Abeta(1- 42) Monomer Adsorbed on the Self-assembled Monolayers

Document Type

Article

Publication Date

Summer 2010

Abstract

Amyloid-β (Aβ) peptide aggregation on the cell membranes is a key pathological event responsible for neuron cell death in Alzheimer’s disease (AD). We present a collection of molecular docking and molecular dynamics simulations to study the conformational dynamics and adsorption behavior of Aβ monomer on the self-assembled monolayer (SAM), in comparison to Aβ structure in bulk solution. Two distinct Aβ conformations (i.e., α-helix and β-hairpin) are selected as initial structures to mimic different adsorption states, whereas four SAM surfaces with different end groups in hydrophobicity and charge distribution are used to examine the effect of surface chemistry on Aβ structure and adsorption. Simulation results show that α-helical monomer displays higher structural stability than β-hairpin monomer on all SAMs, suggesting that the preferential conformation of Aβ monomer could be α-helical or random structure when bound to surfaces. Structural stability and adsorption behavior of Aβ monomer on the SAMs originates from competitive interactions between Aβ and SAM and between SAM and interfacial water, which involve the conformation of Aβ, the surface chemistry of SAM, and the structure and dynamics of interfacial waters. The relative net binding affinity of Aβ with the SAMs is in the favorable order of COOH−SAM > NH2−SAM > CH3−SAM > OH−SAM, highlighting the importance of electrostatic and hydrophobic interactions for driving Aβ adsorption at the SAMs, but both interactions contribute differently to each Aβ−SAM complex. This work provides parallel insights into the understanding of Aβ structure and aggregation on cell membrane.

Volume

26

Issue

15

First Page

12722

Last Page

12732