EC - Methylenetetrahydrofolate—tRNA-(uracil54-C5)-methyltransferase (FADH2-oxidizing)

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IntEnz Enzyme Nomenclature


Accepted name:
methylenetetrahydrofolate—tRNA-(uracil54-C5)-methyltransferase (FADH2-oxidizing)
Other names:
folate-dependent ribothymidyl synthase
methylenetetrahydrofolate-transfer ribonucleate uracil 5-methyltransferase
5,10-methylenetetrahydrofolate:tRNA-UΨC (uracil-5-)-methyl-transferase
5,10-methylenetetrahydrofolate:tRNA (uracil-5-)-methyl-transferase
folate/FAD-dependent tRNA T54 methyltransferase
Systematic name:
5,10-methylenetetrahydrofolate:tRNA (uracil54-C5)-methyltransferase



Up to 25% of the bases in mature tRNA are post-translationally modified or hypermodified. One almost universal post-translational modification is the conversion of U54 into ribothymidine in the TΨC loop, and this modification is found in most species studied to date [2]. Unlike this enzyme, which uses 5,10-methylenetetrahydrofolate and FADH2 to supply the atoms for methylation of U54, EC, tRNA (uracil54-C5)-methyltransferase, uses S-adenosyl-L-methionine.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0047151
CAS Registry Number: 74665-78-4
UniProtKB/Swiss-Prot: (256) [show] [UniProt]


  1. Delk, A.S., Nagle, D.P., Jr. and Rabinowitz, J.C.
    Methylenetetrahydrofolate-dependent biosynthesis of ribothymidine in transfer RNA of Streptococcus faecalis. Evidence for reduction of the 1-carbon unit by FADH2.
    J. Biol. Chem. 255: 4387-4390 (1980). [PMID: 6768721]
  2. Becker, H.F., Motorin, Y., Sissler, M., Florentz, C. and Grosjean, H.
    Major identity determinants for enzymatic formation of ribothymidine and pseudouridine in the TΨ-loop of yeast tRNAs.
    J. Mol. Biol. 274: 505-518 (1997). [PMID: 9417931]
  3. Nishimasu, H., Ishitani, R., Yamashita, K., Iwashita, C., Hirata, A., Hori, H., Nureki, O.
    Atomic structure of a folate/FAD-dependent tRNA T54 methyltransferase.
    Proc. Natl. Acad. Sci. U.S.A. 106: 8180-8185 (2009). [PMID: 19416846]

[EC created 1983, as EC transferred 1984 to EC, modified 2011]