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Updated: Apr 27, 2026

Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
Torque correlation length and stochastic twist dynamics of DNA
Edward J Banigan1, John F Marko2
1Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
Abstract:
We introduce a short correlation length for torque in twisting-stiff biomolecules, which is necessary for the physical property that torque fluctuations be finite in amplitude. We develop a nonequilibrium theory of dynamics of DNA twisting which predicts two crossover time scales for temporal torque correlations in single-molecule experiments. Bending fluctuations can be included, and at linear order we find that they do not affect the twist dynamics. However, twist fluctuations affect bending, and we predict the spatial inhomogeneity of twist, torque, and buckling arising in nonequilibrium "rotor-bead" experiments.
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