Equilibrium and irreversible unzipping of DNA in a nanoporeJ. Mathé1, A. Arinstein2, Y. Rabin2 and A. Meller1
1 Rowland Institute at Harvard, Harvard University - Cambridge, USA
2 Department of Physics, Bar-Ilan University - Ramat-Gan, Israel
received 6 September 2005; accepted in final form 8 November 2005
published online 30 November 2005
We study the unzipping dynamics of individual DNA hairpins using nanopore force spectroscopy at different voltage ramp rates and temperatures. At high ramp rates the critical unzipping voltage is proportional to , where is the voltage ramp. At low ramp values we observe a crossover to another regime with a weaker dependence on . Here we report on the dependence of these two regimes on temperature. Remarkably, the unzipping kinetics can be well described by a simple two-states model that predicts the existence of two asymptotic regimes: quasi-equilibrium unzipping at low-voltage ramps and irreversible unzipping at high ramp rates.
87.14.Gg - DNA, RNA.
82.37.Np - Single molecule reaction kinetics, dissociation, etc.
87.15.He - Dynamics and conformational changes.
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