Summary information and primary citation
- PDB-id
-
5n61;
DSSR-derived features in text and
JSON formats
- Class
- transferase
- Method
- cryo-EM (3.4 Å)
- Summary
- RNA polymerase i initially transcribing complex
- Reference
-
Engel C, Gubbey T, Neyer S, Sainsbury S, Oberthuer C,
Baejen C, Bernecky C, Cramer P (2017): "Structural
Basis of RNA Polymerase I Transcription Initiation."
Cell, 169, 120-131.e22. doi:
10.1016/j.cell.2017.03.003.
- Abstract
- Transcription initiation at the ribosomal RNA promoter
requires RNA polymerase (Pol) I and the initiation factors
Rrn3 and core factor (CF). Here, we combine X-ray
crystallography and cryo-electron microscopy (cryo-EM) to
obtain a molecular model for basal Pol I initiation. The
three-subunit CF binds upstream promoter DNA, docks to the
Pol I-Rrn3 complex, and loads DNA into the expanded active
center cleft of the polymerase. DNA unwinding between the
Pol I protrusion and clamp domains enables cleft
contraction, resulting in an active Pol I conformation and
RNA synthesis. Comparison with the Pol II system suggests
that promoter specificity relies on a distinct
"bendability" and "meltability" of the promoter sequence
that enables contacts between initiation factors, DNA, and
polymerase.
