3NFF: Crystal Structure Of Extended Dimerization Module Of Rna Polymerase I Subcomplex A49/a34.5

The eukaryotic RNA polymerases Pol I, II, and III use different promoters to transcribe different classes of genes. Promoter usage relies on initiation factors, including TFIIF and TFIIE, in the case of Pol II. Here, we show that the Pol I-specific subunits A49 and A34.5 form a subcomplex that binds DNA and is related to TFIIF and TFIIE. The N-terminal regions of A49 and A34.5 form a dimerization module that stimulates polymerase-intrinsic RNA cleavage and has a fold that resembles the TFIIF core. The C-terminal region of A49 forms a "tandem winged helix" (tWH) domain that binds DNA with a preference for the upstream promoter nontemplate strand and is predicted in TFIIE. Similar domains are predicted in Pol III-specific subunits. Thus, Pol I/III subunits that have no counterparts in Pol II are evolutionarily related to Pol II initiation factors and may have evolved to mediate promoter specificity and transcription processivity.
PDB ID: 3NFFDownload
MMDB ID: 84686
PDB Deposition Date: 2010/6/10
Updated in MMDB: 2015/12
Experimental Method:
x-ray diffraction
Resolution: 3.24  Å
Source Organism:
Similar Structures:
Biological Unit for 3NFF: tetrameric; determined by author and by software (PISA)
Molecular Components in 3NFF
Label Count Molecule
Proteins (4 molecules)
RNA Polymerase I Subunit A49
Molecule annotation
RNA Polymerase I Subunit A34.5
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB