Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 36: Biopolymers and Biological Systems

CPP 36.4: Vortrag

Freitag, 29. Februar 2008, 11:15–11:30, C 264

Time-dependent Chain Rupture of Single Double-stranded DNA — •Hua Liang, Nikolai Severin, Igor m. Sokolov, and Jürgen P. Rabe — Department of Physics, Humboldt University, D-12489 Berlin, Germany

The rupture of single covalent bonds is a fundamental scientific issue. Under applied force this is a statistical process with a characteristic time scale depending on the force loading rate. This has been predicted theoretically and proven experimentally for fast force loading rates (1). In the established experimental methods such as dynamic force spectroscopy and dragging molecules with dynamic flow (2), information on the rupture of a single covalent bond is obtained from the breakage of a single polymer chain. However, these methods do not allow to investigate breakage of a covalent bond upon application of a static force. On the other hand, theory predicts that covalent bond rupture under static force is qualitatively different from rupture under dynamic force. Here we report a newly developed method (3) which allows placing a single polymer chain, e.g. a single double-stranded DNA molecule under a static force for an hour or more. The first results elucidate the difference between bond breaking under static force and dynamic force application. The data also allow us insight into the energy landscape of a covalent bond.

1. M. Grandbois et al, Science 283 (1999) 1727-1730;

2. D. Bensimon et al, Physical Review Letters 74 (1995) 4754-4757;

3. N. Severin et al, Nano Letters 6 (2006) 2561-2566.