Development of a Magnetic Tweezer Apparatus for the Manipulation of Single DNA MoleculesPublic Deposited
Magnetic tweezers are a simple yet powerful tool for the micromanipulation of single molecules. In this study, a vertical magnetic tweezer apparatus was constructed for research on the micromechanics of DNA, DNA supercoiling, and DNA-protein interactions. By joining DNA molecules to magnetic beads and attaching these tethers to the wall of a flow cell, discrete forces were applied to extend the molecules by adjusting the vertical position of the magnets, and a torque was applied by rotating the magnets. The mechanical response of the molecule was then observed in real time by measuring the position of the bead along the stretching axis. To achieve a viable system, standard models of DNA extension and supercoiling were tested using the apparatus with bare DNA tethers. In addition to the intrinsic mechanical properties of single DNA molecules, DNA-protein interactions were characterized by injecting a protein solution into the flow cell and measuring the mechanical response of the tethered DNA. Investigations of the enzyme Topoisomerase V and other biomolecules are proposed.