Direct observation of DNA rotation during transcription by Escherichia coli RNA polymerase.

摘要: 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 pitch, myosin an actin filament only poorly. For DNA-based such as RNA polymerase, transcription-induced supercoiling of DNA supports general picture tracking along helix. Here we report direct real-time optical microscopy measurements rate that high-fidelity tracking. Single polymerase molecules attached glass surface >100 revolutions right-handed screw axis double helix rotary torque >5 pN nm. This observation opens possibility resolving individual transcription steps.