Probing protein-protein interactions by dynamic force correlated spectroscopy (FCS)

Abstract

We develop a formalism for single molecule dynamic force spectroscopy to map the energy landscape of protein-protein complex ($P_1$$P_2$). The joint distribution $P({\tau }_1,{\tau }_2)$ of unbinding lifetimes ${\tau }_1$ and ${\tau }_2$ measurable in a compression-tension cycle, which accounts for the internal relaxation dynamics of the proteins under tension, shows that the histogram of ${\tau }_1$ is not Poissonian. The theory is applied to the forced unbinding of protein $P_1$, modeled as a wormlike chain, from $P_1$$P_2$. We propose a new class of experiments which can resolve the effect of internal protein dynamics on the unbinding lifetimes.

12 pages, 3 figures, accepted to Phys. Rev. Lett