Structure of a T7 RNA polymerase elongation complex at 2.9 Å resolution

Academic Article

Abstract

  • The single-subunit bacteriophage T7 RNA polymerase carries out the transcription cycle in an identical manner to that of bacterial and eukaryotic multisubunit enzymes. Here we report the crystal structure of a T7 RNA polymerase elongation complex, which shows that incorporation of an 8-base-pair RNA-DNA hybrid into the active site of the enzyme induces a marked rearrangement of the amino-terminal domain. This rearrangement involves alternative folding of about 130 residues and a marked reorientation (about 130° rotation) of a stable core subdomain, resulting in a structure that provides elements required for stable transcription elongation. A wide opening on the enzyme surface that is probably an RNA exit pathway is formed, and the RNA-DNA hybrid is completely buried in a newly formed, deep protein cavity. Binding of 10 base pairs of downstream DNA is stabilized mostly by long-distance electrostatic interactions. The structure implies plausible mechanisms for the various phases of the transcription cycle, and reveals important structural similarities with the multisubunit RNA polymerases.
  • Published In

  • Nature  Journal
  • Digital Object Identifier (doi)

    Author List

  • Tahlrov TH; Temiakov D; Anikin M; Patlan V; McAllister WT; Vassylyev DG; Yokoyama S
  • Start Page

  • 43
  • End Page

  • 50
  • Volume

  • 420
  • Issue

  • 6911