Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 28: Single Molecule Biophysics
BP 28.4: Vortrag
Donnerstag, 15. März 2018, 10:15–10:30, H 1058
Non-Markovian bond kinetics and its application in dynamic force spectroscopy — •Jakob Tómas Bullerjahn1,2, Sebastian Sturm2, and Klaus Kroy2 — 1Max-Planck-Institut für Biophysik, Frankfurt am Main, Germany — 2Universität Leipzig, Institut für theoretische Physik, Leipzig, Germany
Single-molecule force spectroscopy data are conventionally analyzed using a schematic model, wherein a molecular bond is modeled as a virtual particle diffusing in a one-dimensional free-energy landscape. This simplistic but efficient approach is unable to account for the ``anomalous'' bond-breaking kinetics increasingly observed in high-speed force spectroscopy experiments and simulations, such as a non-exponential distribution of bond lifetimes under constant load. In the traditional framework, the only remedy has been to postulate a multitude of intermediate states. Here, we introduce a complementary approach, namely a rigorous extension of the one-dimensional standard theory that accounts for the transient dynamics of a generic set of coupled degrees of freedom. These ``hidden modes'' affect the reaction dynamics in various ways, depending on their relaxation spectrum. We find exact analytical expressions for pertinent experimental observables, such as the mean rupture force and the rupture force distribution, in two asymptotic limits. They become unconditionally exact at high loading rates, thus providing us with a microscopically consistent theory of rapid force spectroscopy that avoids the usual Markov assumption.