PROSITE documentation PDOC00945
RNA methyltransferase trmA family signatures


In Escherichia coli, the trmA protein is a tRNA (uracil-5-)-methyltransferase (EC that catalyzes the S-adenosylmethionine dependent methylation of U54 in all tRNAs. Orthologs of trmA are found in many eubacterial species. A number of uncharacterized homologs of trmA have been found [1]:

  • Escherichia coli hypothetical protein ygcA and HI0333, the corresponding Haemophilus influenzae protein.
  • Haemophilus influenzae hypothetical protein HI0958.
  • Chlamydia trachomatis protein HOM1.
  • Fission yeast hypothetical protein SpAC4G8.07c.

It is probable that ygcA/HI0333 and HI0958 are probably responsible for the methylation of U747 and U1939 in 23S rRNA. In trmA, a cysteine is known to participate in the catalytic mechanism by forming a covalent adduct to C6 of uracil.

We selected two conserved regions as signature patterns, the first includes the active site cysteine and the second one, located at the C-terminal end, contains a conserved histidine.

Last update:

April 2006 / Patterns revised.


Technical section

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

TRMA_1, PS01230; RNA methyltransferase trmA family signature 1  (PATTERN)

TRMA_2, PS01231; RNA methyltransferase trmA family signature 2  (PATTERN)


1AuthorsGustafsson C. Reid R. Greene P.J. Santi D.V.
TitleIdentification of new RNA modifying enzymes by iterative genome search using known modifying enzymes as probes.
SourceNucleic Acids Res. 24:3756-3762(1996).
PubMed ID8871555

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