Probing protein-protein interactions by dynamic force correlation spectroscopy

We develop a formalism for single molecule dynamic force spectroscopy to map the energy landscape of protein-protein complex (P1P2). The joint distribution P(tau(1),tau(2)) of unbinding lifetimes tau(1) and tau(2), measurable in a compression-tension cycle, which accounts for the internal relaxation dynamics of the proteins under tension, shows that the histogram of tau(1) is not Poissonian. The theory is applied to the forced unbinding of protein P-1, modeled as a wormlike chain, from P1P2. We propose a new class of experiments which can resolve the effect of internal protein dynamics on the unbinding lifetimes.