Magnetic Tweezers Measurement of Single Molecule Torque
- 20 March 2009
- journal article
- letter
- Published by American Chemical Society (ACS) in Nano Letters
- Vol. 9 (4) , 1720-1725
Abstract
Torsional stress in linear biopolymers such as DNA and chromatin has important consequences for nanoscale biological processes. We have developed a new method to directly measure torque on single molecules. Using a cylindrical magnet, we manipulate a novel probe consisting of a nanorod with a 0.1 μm ferromagnetic segment coupled to a magnetic bead. We achieve controlled introduction of turns into the molecule and precise measurement of torque and molecule extension as a function of the number of turns at low pulling force. We show torque measurement of single DNA molecules and demonstrate for the first time measurements of single chromatin fibers.Keywords
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