4BJI: Sfc1-DBD

Transcription of tRNA-encoding genes by RNA polymerase (Pol) III requires the six-subunit general transcription factor IIIC that uses subcomplexes tauA and tauB to recognize two gene-internal promoter elements named A- and B-box. The Schizosaccharomyces pombe tauA subcomplex comprises subunits Sfc1, Sfc4 and Sfc7. The crystal structure of the Sfc1/Sfc7 heterodimer reveals similar domains and overall domain architecture to the Pol II-specific general transcription factor TFIIF Rap30/Rap74. The N-terminal Sfc1/Sfc7 dimerization module consists of a triple beta-barrel similar to the N-terminal TFIIF Rap30/Rap74 dimerization module, whereas the C-terminal Sfc1 DNA-binding domain contains a winged-helix domain most similar to the TFIIF Rap30 C-terminal winged-helix domain. Sfc1 DNA-binding domain recognizes single and double-stranded DNA by an unknown mechanism. Several features observed for A-box recognition by tauA resemble the recognition of promoters by bacterial RNA polymerase, where sigma factor unfolds double-stranded DNA and stabilizes the non-coding DNA strand in an open conformation. Such a function has also been proposed for TFIIF, suggesting that the observed structural similarity between Sfc1/Sfc7 and TFIIF Rap30/Rap74 might also reflect similar functions.
PDB ID: 4BJIDownload
MMDB ID: 112174
PDB Deposition Date: 2013/4/18
Updated in MMDB: 2013/11
Experimental Method:
x-ray diffraction
Resolution: 1.45  Å
Source Organism:
Similar Structures:
Biological Unit for 4BJI: monomeric; determined by author and by software (PISA)
Molecular Components in 4BJI
Label Count Molecule
Protein (1 molecule)
Transcription Factor TAU Subunit Sfc1(Gene symbol: sfc1)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB