PROSITE documentation PDOC00896
RNA polymerases beta chain signature


DNA-dependent RNA polymerases (EC are ubiquitous enzymes necessary for the transcription of genomic DNA into RNA. Most RNA polymerases are multimeric enzymes and are composed of a variable number of subunits. However the two largest subunits (generally known as α and β chains) are present in all known multimeric RNA polymerases. The β chain is currently known in:

  • Eubacterial RNA polymerase β chain (gene rpoB).
  • Plants and algal chloroplast RNA polymerase β chain (gene rpoB).
  • Eukaryotes RNA polymerases I, II and III second largest subunits.
  • Archebacterial RNA polymerase subunit B (gene rpoB) or B' (gene rpoB1).
  • Poxviruses RNA polymerase 132 Kd subunit (gene RPO132).
  • Baculoviruses RNA polymerase subunit LEF-8.
  • African swine fever virus RNA polymerase subunit EP1242L.
  • Fungal plasmid-encoded RNA polymerases.

The β chains are proteins of from 900 to 1400 amino acid residues. A well conserved region of 13 residues that contains two conserved lysines and which is thought to be part of the active site is located in the C-terminal part of all β chains [1]. We have used this region as a signature pattern.

Last update:

December 2004 / Pattern and text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

RNA_POL_BETA, PS01166; RNA polymerases beta chain signature  (PATTERN)


1AuthorsPassarelli A.L. Todd J.W. Miller L.K.
TitleA baculovirus gene involved in late gene expression predicts a large polypeptide with a conserved motif of RNA polymerases.
SourceJ. Virol. 68:4673-4678(1994).
PubMed ID8207843

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