Theoretical analysis of dynamic force spectroscopy experiments on ligand-receptor complexes

The forced rupture of single chemical bonds in biomolecular compounds (e.g. ligand-receptor systems) as observed in dynamic force spectroscopy experiments is addressed. Under the assumption that the probability of bond rupture depends only on the instantaneously acting force, a data collapse onto a single master curve is predicted. For rupture data obtained experimentally by dynamic AFM force spectroscopy of a ligand-receptor bond between a DNA and a regulatory protein we do not find such a collapse. We conclude that the above mentioned, generally accepted assumption is not satisfied and we discuss possible explanations.