Direct determination of DNA twist-stretch coupling
Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
Accepted: 10 March 1997
The symmetries of the DNA double helix require a new term in its linear response to stress: the coupling between twist and stretch. Recent experiments with torsionally constrained single molecules give the first direct measurement of this important material parameter. We extract its value from a recent experiment of Strick et al. (Science, 271 (1996) 1835) and find agreement with an independent experimental estimate recently given by Marko. We also present a very simple microscopic theory predicting a value comparable to the one observed.
PACS: 87.15.-v – Molecular biophysics / 87.10.+e – General, theoretical, and mathematical biophysics (including logic of biosystems, quantum biology, and relevant aspects of thermodynamics, information theory, cybernetics, and bionics) / 87.15.By – Structure, bonding, conformation, configuration, and isomerism of biomolecules
© EDP Sciences, 1997