PROSITE documentation PDOC00410
Bacteriophage-type RNA polymerase family active site signatures


Many forms of RNA polymerase (EC are known. Most RNA polymerases are multimeric enzymes, but there is a family of single chain polymerases, which are evolutionary related, and which originate from bacteriophages or from mitochondria. The RNA polymerases that belong to this family are [1]:

  • Podoviridae bacteriophages T3, T7, and K11 polymerase.
  • Bacteriophage SP6 polymerase.
  • Vertebrate mitochondrial polymerase (gene POLRMT).
  • Fungal mitochondrial polymerase (gene RPO41).
  • Polymerases encoded on mitochondrial linear DNA plasmids in various fungi and plants: Agaricus bitorquis pEM, Claviceps purpurea pClK1, Neurospora crassa Kalilo; Neurospora intermedia Maranhar and maize S-2).

Two conserved aspartate and one lysine residue have been shown [2,3] to be part of the active site of T7 polymerase. We have used the regions around the first aspartate and around the lysine as signature patterns for this family of polymerases.

Last update:

July 1999 / Text revised.


Technical section

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

RNA_POL_PHAGE_1, PS00900; Bacteriophage-type RNA polymerase family active site signature 1  (PATTERN)

RNA_POL_PHAGE_2, PS00489; Bacteriophage-type RNA polymerase family active site signature 2  (PATTERN)


1AuthorsMcAllister W.T. Raskin C.A.
TitleThe phage RNA polymerases are related to DNA polymerases and reverse transcriptases.
SourceMol. Microbiol. 10:1-6(1993).
PubMed ID7526118

2AuthorsMaksimova T.G. Mustayev A.A. Zaychikov E.F. Lyakhov D.L. Tunitskaya V.L. Akbarov A.K. Luchin S.V. Rechinsky V.O. Chernov B.K. Kochetkov S.N.
TitleLys631 residue in the active site of the bacteriophage T7 RNA polymerase. Affinity labeling and site-directed mutagenesis.
SourceEur. J. Biochem. 195:841-847(1991).
PubMed ID1847871

3AuthorsSousa R. Chung Y.J. Rose J.P. Wang B.-C.
TitleCrystal structure of bacteriophage T7 RNA polymerase at 3.3 A resolution.
SourceNature 364:593-599(1993).
PubMed ID7688864

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