Structure of a (Cys3His) zinc ribbon, a ubiquitous motif in archaeal and eucaryal transcription

Protein Sci. 2000 Sep;9(9):1743-52. doi: 10.1110/ps.9.9.1743.

Abstract

Transcription factor IIB (TFIIB) is an essential component in the formation of the transcription initiation complex in eucaryal and archaeal transcription. TFIIB interacts with a promoter complex containing the TATA-binding protein (TBP) to facilitate interaction with RNA polymerase II (RNA pol II) and the associated transcription factor IIF (TFIIF). TFIIB contains a zinc-binding motif near the N-terminus that is directly involved in the interaction with RNA pol II/TFIIF and plays a crucial role in selecting the transcription initiation site. The solution structure of the N-terminal residues 2-59 of human TFIIB was determined by multidimensional NMR spectroscopy. The structure consists of a nearly tetrahedral Zn(Cys)3(His)1 site confined by type I and "rubredoxin" turns, three antiparallel beta-strands, and disordered loops. The structure is similar to the reported zinc-ribbon motifs in several transcription-related proteins from archaea and eucarya, including Pyrococcus furiosus transcription factor B (PfTFB), human and yeast transcription factor IIS (TFIIS), and Thermococcus celer RNA polymerase II subunit M (TcRPOM). The zinc-ribbon structure of TFIIB, in conjunction with the biochemical analyses, suggests that residues on the beta-sheet are involved in the interaction with RNA pol II/TFIIF, while the zinc-binding site may increase the stability of the beta-sheet.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Motifs*
  • Amino Acid Sequence
  • Archaea / genetics*
  • Cysteine / chemistry*
  • Eukaryotic Cells / metabolism
  • Histidine / chemistry*
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Structure, Secondary
  • Sequence Homology, Amino Acid
  • Transcription Factor TFIIB
  • Transcription Factors / chemistry
  • Transcription, Genetic*
  • Zinc / chemistry*

Substances

  • Transcription Factor TFIIB
  • Transcription Factors
  • Histidine
  • Zinc
  • Cysteine