Comparison of three competing dynamic force spectroscopy models to study binding forces of amyloid-β (1-42)

We performed single molecule dynamic force spectroscopy experiments to study the dimerization of two amyloid-beta (1-42) peptides and compared three different theoretical models used to fit experimental data: Bell-Evans, Dudko-Hummer-Szabo, and Friddle-De Yoreo. Using these models we extracted values of the dissociation rate at zero force, k(0), and height and the width of the energy barrier, Delta G and X-beta. We show the importance of including the effect of the linker molecule. All three models corrected for the linker effect give comparable results for x(beta) and show more discrepancy for k(0) and Delta G values, Delta G parameter correlates well between Dudko-Hummer-Szabo and Friddle-De Yoreo models but differs for the Bell-Evans model.