title: Mechanics of binding of a single integration-host-factor protein to DNA.
abstract: We report on a single-molecule experiment where we directly observe local bending of a 76 base pair DNA oligomer caused by specific binding of a single integration-host-factor (IHF) protein. The conformational change of the DNA is detected by optically monitoring the displacement of a micron size bead tethered to a surface by the DNA. Since in the bound state the DNA loops around the IHF, a mechanical tension on the DNA tends to eject the protein. We measure how the rate for the protein to fall off the DNA depends on the mechanical tension in the DNA, gaining insight into the energy landscape for this molecular bond. Our method further demonstrates a new paradigm of molecular detection, where ligand binding is detected through the conformational change induced in the probe molecule. Here this allows the detection of single, unlabeled proteins.
authors.affiliation: Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, CA 90095-1547, USA.
authors.forename: Sanhita
authors.initials: S
authors.lastname: Dixit
authors.forename: Mukta
authors.initials: M
authors.lastname: Singh-Zocchi
authors.forename: Jeungphill
authors.initials: J
authors.lastname: Hanne
authors.forename: Giovanni
authors.initials: G
authors.lastname: Zocchi
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D034982:Integration Host Factors / Q000737:chemistry* / Q000378:metabolism; D009690:Nucleic Acid Conformation
chemical_list: D034982:Integration Host Factors; D004247:DNA