title: Direct observation of DNA rotation during transcription by Escherichia coli RNA polymerase.
abstract: Helical filaments driven by linear molecular motors are anticipated to rotate around their axis, but rotation consistent with the helical pitch has not been observed. 14S dynein and non-claret disjunctional protein (ncd) rotated a microtubule more efficiently than expected for its helical pitch, and myosin rotated an actin filament only poorly. For DNA-based motors such as RNA polymerase, transcription-induced supercoiling of DNA supports the general picture of tracking along the DNA helix. Here we report direct and real-time optical microscopy measurements of rotation rate that are consistent with high-fidelity tracking. Single RNA polymerase molecules attached to a glass surface rotated DNA for >100 revolutions around the right-handed screw axis of the double helix with a rotary torque of >5 pN nm. This real-time observation of rotation opens the possibility of resolving individual transcription steps.
authors.affiliation: Department of Physics, Faculty of Science and Technology, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522, Japan. yharada@rinshoken.or.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Harada
authors.forename: O
authors.initials: O
authors.lastname: Ohara
authors.forename: A
authors.initials: A
authors.lastname: Takatsuki
authors.forename: H
authors.initials: H
authors.lastname: Itoh
authors.forename: N
authors.initials: N
authors.lastname: Shimamoto
authors.forename: K
authors.initials: K
authors.lastname: Kinosita
mesh_terms: D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D005456:Fluorescent Dyes; D008280:Magnetics; D008853:Microscopy; D008863:Microspheres; D020409:Molecular Motor Proteins; D009690:Nucleic Acid Conformation; D012313:RNA / Q000378:metabolism; D012399:Rotation; D014158:Transcription, Genetic
chemical_list: D005456:Fluorescent Dyes; D020409:Molecular Motor Proteins; D012313:RNA; D004247:DNA; D012321:DNA-Directed RNA Polymerases