Uncovering Amyloid-β Interactions: Gray versus White Matter.

Alzheimer's disease is characterized by the accumulation of amyloid plaques in the brain. Recent studies suggest that amyloid-β (Aβ) peptides interact with cell membranes, potentially catalyzing plaque formation. However, the effect of varying cell membrane compositions on this catalytic process requires further investigation. Using molecular dynamics simulations, we demonstrate that a model gray matter membrane significantly influences the secondary structure of β-amyloid peptides. Notably, residues Asp1 and Glu22 play crucial roles in the membrane interaction. Glutamic acid at position 22, located in the middle of the peptide chain, appears to promote the formation of β-hairpin conformations, which are critical for aggregation. Additionally, our simulations reveal that the model white matter membrane allows a spontaneous insertion of segments of the peptide into the membrane, suggesting that membrane interaction not only alters the peptide structure but may also compromise membrane integrity. Our results show that the different membrane compositions in the brain may play different roles when interacting with β-amyloid peptides.