Statistical Breakage of Single Protein A-IgG Bonds Reveals Crossover from Spontaneous to Force-Induced Bond Dissociation

Abstract
Dynamic force spectroscopy was applied to single specific bonds between immunoglobulins of type G and protein A, a staphylococcal receptor for IgG. The resulting spectra of yield forces indicated the crossover from force induced to spontaneous bond dissociation. Moreover, failure of unloaded bonds was observed directly. Extrapolation to vanishing loading rate and direct observation yielded coinciding results.