IUBMB Enzyme Nomenclature


Accepted name: S-adenosylmethionine:tRNA ribosyltransferase-isomerase

Reaction: S-adenosyl-L-methionine + 7-aminomethyl-7-carbaguanosine34 in tRNA = L-methionine + adenine + epoxyqueuosine34 in tRNA

For diagram of reaction click here and mechanism click here.

Glossary: 7-aminomethyl-7-carbaguanine = preQ1 = 7-aminomethyl-7-deazaguanine
epoxyqueosine = oQ

Other name(s): QueA enzyme; queuosine biosynthesis protein QueA

Systematic name: S-adenosyl-L-methionine:7-aminomethyl-7-deazaguanosine ribosyltransferase (ribosyl isomerizing; L-methionine, adenine releasing)

Comments: The reaction is a combined transfer and isomerization of the ribose moiety of S-adenosyl-L-methionine to the modified guanosine base in the wobble position in tRNAs specific for Tyr, His, Asp or Asn. It is part of the queuosine biosynthesis pathway.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Slany, R.K., Bosl, M., Crain, P.F. and Kersten, H. A new function of S-adenosylmethionine: the ribosyl moiety of AdoMet is the precursor of the cyclopentenediol moiety of the tRNA wobble base queuine. Biochemistry 32 (1993) 7811-7817. [PMID: 8347586]

2. Slany, R.K., Bosl, M. and Kersten, H. Transfer and isomerization of the ribose moiety of AdoMet during the biosynthesis of queuosine tRNAs, a new unique reaction catalyzed by the QueA protein from Escherichia coli. Biochimie 76 (1994) 389-393. [PMID: 7849103]

3. Kinzie, S.D., Thern, B. and Iwata-Reuyl, D. Mechanistic studies of the tRNA-modifying enzyme QueA: a chemical imperative for the use of AdoMet as a "ribosyl" donor. Org. Lett. 2 (2000) 1307-1310. [PMID: 10810734]

4. Van Lanen, S.G. and Iwata-Reuyl, D. Kinetic mechanism of the tRNA-modifying enzyme S-adenosylmethionine:tRNA ribosyltransferase-isomerase (QueA). Biochemistry 42 (2003) 5312-5320. [PMID: 12731872]

5. Mathews, I., Schwarzenbacher, R., McMullan, D., Abdubek, P., Ambing, E., Axelrod, H., Biorac, T., Canaves, J.M., Chiu, H.J., Deacon, A.M., DiDonato, M., Elsliger, M.A., Godzik, A., Grittini, C., Grzechnik, S.K., Hale, J., Hampton, E., Han, G.W., Haugen, J., Hornsby, M., Jaroszewski, L., Klock, H.E., Koesema, E., Kreusch, A., Kuhn, P., Lesley, S.A., Levin, I., Miller, M.D., Moy, K., Nigoghossian, E., Ouyang, J., Paulsen, J., Quijano, K., Reyes, R., Spraggon, G., Stevens, R.C., van den Bedem, H., Velasquez, J., Vincent, J., White, A., Wolf, G., Xu, Q., Hodgson, K.O., Wooley, J. and Wilson, I.A. Crystal structure of S-adenosylmethionine:tRNA ribosyltransferase-isomerase (QueA) from Thermotoga maritima at 2.0 Å resolution reveals a new fold. Proteins 59 (2005) 869-874. [PMID: 15822125]

6. Grimm, C., Ficner, R., Sgraja, T., Haebel, P., Klebe, G. and Reuter, K. Crystal structure of Bacillus subtilis S-adenosylmethionine:tRNA ribosyltransferase-isomerase. Biochem. Biophys. Res. Commun. 351 (2006) 695-701. [PMID: 17083917]

[EC created 2012]

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