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(τ₁,τ₂) of unbinding lifetimes τ₁ and τ₂, measurable in a compression-tension cycle, which accounts for the internal relaxation dynamics of the proteins under tension, shows that the histogram of τ₁ is not Poissonian. The theory is applied to the forced unbinding of protein P₁, 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.