2017/04/26 by Hane, Francis, Tran, Gary, Attwood, Simon +1
#Biological Physics (physics.bio-ph) #FOS: Physical sciences
paper · doi:10.48550/arxiv.1704.08317
The link between metals, Alzheimers disease (AD) and its implicated protein, amyloid \beta (A\beta), is complex and highly studied. AD is believed to occur as a result of the misfolding and aggregation of A\beta. The dyshomeostasis of metal ions and their propensity to interact with A\beta has also been implicated in AD. In this work, we use single molecule atomic force spectroscopy to measure the rupture force required to dissociate two A\beta (1 42) peptides in the presence of copper ions, Cu2+. In addition, we use atomic force microscopy to resolve the aggregation of A\beta formed. Previous research has shown that metal ions decrease the lag time associated with A\beta aggregation. We show that with the addition of copper ions the unbinding force increases notably. This suggests that the reduction of lag time associated with A\beta aggregation occurs on a single molecule level as a result of an increase in binding forces during the very initial interactions between two A\beta peptides. We attribute these results to copper ions acting as a bridge between the two peptide molecules, increasing the stability of the peptide-peptide complex.