We discuss the denaturation of long, double-stranded DNA pulled apart by a constant force. When the force approaches a critical threshold, a remarkable unzipping transition occurs which is strongly influenced by randomness in the base pair sequence.[1] The DNA unzips via a series of discrete jumps and plateaus which allow it to reach successively deeper energy minima. Above the threshold force, the dynamics of unzipping is related to that of a particle diffusing in a random force field. Recently, the first observations of this striking behavior, carried out on several identical molecules in parallel, have been reported.[2] The position and duration of the pauses in the separation are reproducible from molecule to molecule and depend on the applied force. For small forces, the DNA remains in a partially unzipped state. We expect similar energy landscapes together with anomalous drift and diffusion for certain molecular motors near the stall force.
[1] D. K. Lubensky and D. R. Nelson, Phys. Rev. E 65, 031917 (2002).
[2] C. Danilowicz et. al. Prod. Natl. Acad. Sci. 100, 1694 (2003).
We discuss the denaturation of long, double-stranded DNA pulled apart by a constant force. When the force approaches a critical threshold, a remarkable unzipping transition occurs which is strongly influenced by randomness in the base pair sequence.[1] The DNA unzips via a series of discrete jumps and plateaus which allow it to reach successively deeper energy minima. Above the threshold force, the dynamics of unzipping is related to that of a particle diffusing in a random force field. Recently, the first observations of this striking behavior, carried out on several identical molecules in parallel, have been reported.[2] The position and duration of the pauses in the separation are reproducible from molecule to molecule and depend on the applied force. For small forces, the DNA remains in a partially unzipped state. We expect similar energy landscapes together with anomalous drift and diffusion for certain molecular motors near the stall force.
[1] D. K. Lubensky and D. R. Nelson, Phys. Rev. E 65, 031917 (2002).
[2] C. Danilowicz et. al. Prod. Natl. Acad. Sci. 100, 1694 (2003).
