In order to open the DNA double helix mechanically, a molecular construction is prepared which allows specific attachment of the two complementary strands of an individual molecule to two differentμm-sized beads. The beads are separately captured by a dual optical trap, thus holding the DNA construction in solution. The opening of a molecule is obtained by increasing the distance between the traps, one trap being slowly moved while the other is held fixed. Force is measured to sub-piconewton precision by back focal plane interferometry of the bead in the fixed trap. The experiment allows us to measure base sequence-dependent force signal. In this chapter, important technical aspects of this type of single-molecule force measurements are considered.
CITATION STYLE
Cissé, I., Mangeol, P., & Bockelmann, U. (2011). DNA Unzipping and Force Measurements with a Dual Optical Trap. In Methods in Molecular Biology (Vol. 783, pp. 45–61). Humana Press Inc. https://doi.org/10.1007/978-1-61779-282-3_3
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