Probing the salt dependence of the torsional stiffness of DNA by multiplexed magnetic torque tweezers

Kriegel F, Ermann N, Forbes R, Dulin D, Dekker NH, Lipfert J (2017)

Publication Type: Journal article

Publication year: 2017

Journal

Nucleic Acids Research Oxford University Press

Book Volume: 45

Pages Range: 5920-5929

Journal Issue: 10

DOI: 10.1093/nar/gkx280

Abstract

The mechanical properties of DNA fundamentally constrain and enable the storage and transmission of genetic information and its use in DNA nanotechnology. Many properties of DNA depend on the ionic environment due to its highly charged backbone. In particular, both theoretical analyses and direct single-molecule experiments have shown its bending stiffness to depend on salt concentration. In contrast, the salt-dependence of the twist stiffness of DNA is much less explored. Here, we employ optimized multiplexed magnetic torque tweezers to study the torsional stiffness of DNA under varying salt conditions as a function of stretching force. At low forces (<3 pN), the effective torsional stiffness is ~10% smaller for high salt conditions (500 mM NaCl or 10 mM MgCl2) compared to lower salt concentrations (20 mM NaCl and 100 mM NaCl). These differences, however, can be accounted for by taking into account the known salt dependence of the bending stiffness. In addition, the measured high-force (6.5 pN) torsional stiffness values of C = 103 ± 4 nm are identical, within experimental errors, for all tested salt concentration, suggesting that the intrinsic torsional stiffness of DNA does not depend on salt.

Authors with CRIS profile

David Dulin Interdisziplinäres Zentrum für Klinische Forschung IZKF Nachwuchsgruppe 2 Prof. Dr. Dulin

Involved external institutions

Ludwig-Maximilians-Universität (LMU) DE Germany (DE) Delft University of Technology (TU Delft) NL Netherlands (NL)

How to cite

APA:

Kriegel, F., Ermann, N., Forbes, R., Dulin, D., Dekker, N.H., & Lipfert, J. (2017). Probing the salt dependence of the torsional stiffness of DNA by multiplexed magnetic torque tweezers. Nucleic Acids Research, 45(10), 5920-5929. https://dx.doi.org/10.1093/nar/gkx280

MLA:

Kriegel, Franziska, et al. "Probing the salt dependence of the torsional stiffness of DNA by multiplexed magnetic torque tweezers." Nucleic Acids Research 45.10 (2017): 5920-5929.

BibTeX: Download