Regensburg 2019 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 36: Condensed-matter simulations augmented by advanced statistical methodologies (joint session DY/CPP)

DY 36.12: Vortrag

Mittwoch, 3. April 2019, 18:15–18:30, H20

The temperature dependence of the mechanical unfolding of a supramolecular complex studied by molecular simulations — Takashi Kato, Ken Schäfer, Stefan Jaschonek, and •Gregor Diezemann — Institu für Physikalische Chemie, Universität Mainz

The conformational dynamics of supramolecular complexes can be studied on a single molecule level using the techniques of dynamic force spectroscopy and important kinetic information can be extracted. Using models for the free energy landscape of the system as a function of the molecular extension it is possible to obtain parameters like the bare unfolding rate, the activation free energy in the force-free case and also the distance between the folded configuration and the transition state. In the present work we performed molecular simulations of the mechanical unfolding of a model molecular complex, a pair of interlocked calixarene catenanes. From rupture force distributions the kinetic rates for the opening transition were extacted for varying parameters of the pulling device. In order to be able to perform a model-free analysis we performed simulations over a broad range of temperatures and found Arrhenius behavior for the kinetic rates. This allows to determine the activation free energy and the bare rate independently as a function of the force without using specific models for the shape of the energy landscape. We discuss our findings in light of the models that are usually used in the analysis of force dependent kinetic rates obtained from experimental or simulation data.