A ratchet mechanism of transcription elongation and its control

Gil Bar-Nahum, Vitaly Epshtein, Andrei E. Ruckenstein, Ruslan Rafikov, Arkady Mustaev, Evgeny Nudler

Research output: Contribution to journalArticlepeer-review

264 Scopus citations


RNA chain elongation is a highly processive and accurate process that is finely regulated by numerous intrinsic and extrinsic signals. Here we describe a general mechanism that governs RNA polymerase (RNAP) movement and response to regulatory inputs such as pauses, terminators, and elongation factors. We show that E.coli RNAP moves by a complex Brownian ratchet mechanism, which acts prior to phosphodiester bond formation. The incoming substrate and the flexible F bridge domain of the catalytic center serve as two separate ratchet devices that function in concert to drive forward translocation. The adjacent G loop domain controls F bridge motion, thus keeping the proper balance between productive and inactive states of the elongation complex. This balance is critical for cell viability since it determines the rate, processivity, and fidelity of transcription.

Original languageEnglish (US)
Pages (from-to)183-193
Number of pages11
Issue number2
StatePublished - Jan 28 2005
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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