科研之友
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摘要
Amyloid-beta (A beta) 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 A beta monomer on the self-assembled monolayer (SAM), in comparison to A beta structure in bulk solution. Two distinct A beta conformations (i.e., alpha-helix and beta-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 A beta structure and adsorption. Simulation results show that a-helical monomer displays higher structural stability than beta-hairpin monomer on all SAMs, suggesting that the preferential conformation of A beta monomer could be a-helical or random structure when bound to surfaces. Structural stability and adsorption behavior of A beta monomer on the SAMs originates from competitive interactions between A beta and SAM and between SAM and interfacial water, which involve the conformation of A beta, the surface chemistry of SAM, and the structure and dynamics of interfacial waters. The relative net binding affinity of A beta 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 A beta adsorption at the SAMs, but both interactions contribute differently to each A beta SAM complex. This work provides parallel insights into the understanding of A beta structure and aggregation on cell membrane.
- 出版日期2010-8-3
