Dresden 2014 – scientific programme

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BP: Fachverband Biologische Physik

BP 5: Protein structure and dynamics I

BP 5.1: Talk

Monday, March 31, 2014, 15:00–15:15, ZEU 250

Rapid force spectroscopy — •Jakob Tómas Bullerjahn, Sebastian Sturm, and Klaus Kroy — Universität Leipzig, Institut für theoretische Physik, 04103 Leipzig, Germany

Dynamic force spectroscopy, the examination of intermolecular binding affinities and kinetics through single-molecule manipulation techniques, is a valuable complement to more traditional means of structural investigation. In contrast to scattering techniques or classical microscopy, it allows the experimentalist to gauge the dynamic and plastic behavior of a given material by directly probing the underlying free energy landscape, on a molecular scale. However, in spite of the strong forces required to do so, established theories of force spectroscopy still build on Kramers’ quasistatic theory. Originally devised for the usually slow process of spontaneous unbinding, it is set to break down at high loading rates. We extend these theories to fast loading rates by explicitly resolving the nonequilibrium internal bond dynamics. Our analytical results turn out to hold almost universally, for fast and slow loading alike, breaking down only within a narrow parameter range close to a well-defined critical loading rate. Their large range of applicability moreover renders them an ideal companion to Bayesian methods of data analysis. Yielding highly competitive results, even without precise a priori knowledge of the underlying energy landscape, our generic analytical theory suggests itself as a unified framework for analyzing and comparing force spectroscopy data from a wide range of experiments and simulations.