Summary information and primary citation
- PDB-id
-
5m5w;
DSSR-derived features in text and
JSON formats
- Class
- transcription
- Method
- cryo-EM (3.8 Å)
- Summary
- RNA polymerase i open complex
- Reference
-
Tafur L, Sadian Y, Hoffmann NA, Jakobi AJ, Wetzel R,
Hagen WJ, Sachse C, Muller CW (2016): "Molecular
Structures of Transcribing RNA Polymerase I."
Mol. Cell, 64, 1135-1143. doi:
10.1016/j.molcel.2016.11.013.
- Abstract
- RNA polymerase I (Pol I) is a 14-subunit enzyme that
solely synthesizes pre-ribosomal RNA. Recently, the crystal
structure of apo Pol I gave unprecedented insight into its
molecular architecture. Here, we present three cryo-EM
structures of elongating Pol I, two at 4.0 Å and one
at 4.6 Å resolution, and a Pol I open complex at
3.8 Å resolution. Two modules in Pol I mediate the
narrowing of the DNA-binding cleft by closing the clamp
domain. The DNA is bound by the clamp head and by the
protrusion domain, allowing visualization of the upstream
and downstream DNA duplexes in one of the elongation
complexes. During formation of the Pol I elongation
complex, the bridge helix progressively folds, while the
A12.2 C-terminal domain is displaced from the active site.
Our results reveal the conformational changes associated
with elongation complex formation and provide additional
insight into the Pol I transcription cycle.
