Regensburg 2010 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 6: Posters: DNA and DNA Enzymes
BP 6.5: Poster
Montag, 22. März 2010, 17:15–20:00, Poster B1
Binding Kinetics of Bisintercalator Triostin A Measurements with Optical Tweezers — •Andy Sischka1, Christoph Kleimann2, André Spiering1, Katja Tönsing1, Norbert Sewald3, Ulf Diedrichsen4, and Dario Anselmetti1 — 1Experimental Biophysics and Applied Nanosciences, Bielefeld University, 33615 Bielefeld, Germany — 2Institut für Bio- und Nanosysteme (IBN-3), Forschungszentrum Jülich, 52425 Jülich, Germany — 3Organic and Bioorganic Chemistry, Bielefeld University, 33615 Bielefeld, Germany — 4Organic and Biomolecular Chemistry, Göttingen University, 37077 Göttingen, Germany
We present single molecule binding studies where the intercalative binding kinetics of Triostin A to λ-DNA was investigated by measuring the force/extension response with our optical tweezers system [1]. These curves were analyzed based on a method for monointercalators that was extended to bisintercalators. Our measurements with Triostin A showed non-equilibrium phenomena, resulting in large hysteresis effects during a fast stretching/relaxation cycle, whereas at slow velocities, the system reaches an equilibrium state and the hysteresis vanishes. Subsequent binding analysis reveals an exponential dependence of the association constant on the external force as well as a decreasing binding site size. To explain the high-force binding site size, a new model for bisintercalation of Triostin A is proposed, where the deformation of the Triostin A binding site could thereby repeal the neighbor exclusion principle, leading to closer packaging of Triostin A.
[1] Ch. Kleimann, A. Sischka et al., Biophys.J 97, 2780-2784 (2009)