Structural Transitions of a Twisted and Stretched DNA Molecule

J. F. Léger; G. Romano; A. Sarkar; J. Robert; L. Bourdieu; D. Chatenay; J. F. Marko

doi:10.1103/PhysRevLett.83.1066

Structural Transitions of a Twisted and Stretched DNA Molecule

J. F. Léger, G. Romano, A. Sarkar, J. Robert, L. Bourdieu, D. Chatenay, and J. F. Marko

Phys. Rev. Lett. 83, 1066 – Published 2 August 1999

Abstract

We report results of a micromanipulation study of single double-helical DNA molecules at forces up to 150 pN. Depending on whether the DNA winding is allowed to relax, or held fixed, qualitatively different structural transitions are observed. By studying the transitions as a function of winding the different DNA structures underlying them are characterized; this allows us to report the first estimate of $S - DNA$ helicity. A model is introduced to describe these transitions; in addition to $B - DNA$ , we find that four DNA states are needed to describe the experiments.

Received 10 December 1998

DOI:https://doi.org/10.1103/PhysRevLett.83.1066

Authors & Affiliations

J. F. Léger¹, G. Romano¹, A. Sarkar², J. Robert¹, L. Bourdieu¹, D. Chatenay¹, and J. F. Marko²

¹L.D.F.C., UMR CNRS 7506 and Université Louis Pasteur, Institut de Physique, 3 rue de l'Université, 67000 Strasbourg, France
²Department of Physics, MC 273, University of Illinois, 845 West Taylor Street, Chicago, Illinois 60607-7059