Dresden 2014 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 7: Posters: Cell adhesion, mechanics and migration
BP 7.10: Poster
Montag, 31. März 2014, 17:30–19:30, P3
Two barriers or not? Dynamic force spectrosopy on the integrin α7β1 invasin complex — •Agnieszka Ligezowska2, Kristian Boye1, Johannes A. Eble3, Bernd Hoffmann2, Beate Klösgen1, and Rudolf Merkel2 — 1MEMPHYS Center for Biomembrane Physics, University of Southern Denmark, DK-5230 Odense M, Denmark — 2Institute of Complex Systems 7: Biomechanics, Forschungszentrum Jülich, D-52425 Jülich, Germany — 3Center for Molecular Medicine, Frankfurt University, D-60590 Frankfurt am Main, Germany
Dynamic force spectroscopy was applied to test the force driven dissociation of the specific bond between integrin α7β1 and the bacterial protein invasin. Using biomembrane force probe, the single bonds were exposed to 14 different loading rates ranging from 18pN/s to 5.3nN/s. Plotting median yield forces, ranging from 8pN to 72pN, against the logarithm of the corresponding force loading rate revealed two linear regimes seemingly representing two energy barriers. Thermal fluctuations of the ultra-soft force transducer and the environment set a natural detection limit of the technique. The lowest rupture forces were unavoidably obscured by thermal fluctuations that might have led to an artificial shift towards higher forces. An in-depth data analysis including the detection limits showed that the second linear regime might be entirely due to the force shift effect. It is not necessarily rooted in the physical properties of the bond system. The bond dissociation could be well described by traverse over a single barrier [1].
[1] K. Boye et al., Biophys. J. 105, 2771-2780 (2013)