Behavior of complex knots in single DNA molecules.

Phys Rev Lett

Department of Applied Physics, California Institute of Technology, Pasadena, California 91125, USA.

Published: December 2003

We used optical tweezers to tie individual DNA molecules in knots. Although these knots become highly localized under tension, they remain surprisingly mobile and undergo thermal diffusion with classical random walk statistics. The diffusion constants of knots with different complexities correlate with theoretical calculations of knot sizes. We show that this correlation can be explained by a simple hydrodynamical model of "self-reptation" of the knot along a polymer.

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http://dx.doi.org/10.1103/PhysRevLett.91.265506DOI Listing

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