Nature Methods

Publication date: 2010-12
Pages: 977 -
ISSN: 1548-7091, 1548-7105 PMID: 20953173
DOI: 10.1038/NMETH.1520
Publisher: Nature Pub. Group

Author:

Lipfert, Jan
Kerssemakers, Jacob WJ ; Jager, Tessa ; Dekker, Nynke H

Keywords:

Science & Technology, Life Sciences & Biomedicine, Biochemical Research Methods, Biochemistry & Molecular Biology, OPTICAL TWEEZERS, SUPERCOILED DNA, MOLECULE, ELASTICITY, RIGIDITY, IB, DNA, Kinetics, Magnetics, Maillard Reaction, Microscopy, Video, Rec A Recombinases, Rotation, Stress, Mechanical, Torque, 06 Biological Sciences, 10 Technology, 11 Medical and Health Sciences, Developmental Biology

Abstract:

We introduce magnetic torque tweezers, which enable direct single-molecule measurements of torque. Our measurements of the effective torsional stiffness C of dsDNA indicated a substantial force dependence, with C = approximately 40 nm at low forces up to C = approximately 100 nm at high forces. The initial torsional stiffness of RecA filaments was nearly twofold larger than that for dsDNA, yet at moderate torques further build-up of torsional strain was prevented.