IUBMB Enzyme Nomenclature


Accepted name: tRNA (adenine57-N1/adenine58-N1)-methyltransferase

Reaction: 2 S-adenosyl-L-methionine + adenine57/adenine58 in tRNA = 2 S-adenosyl-L-homocysteine + N1-methyladenine57/N1-methyladenine58 in tRNA

Other name(s): TrmI; PabTrmI; AqTrmI; MtTrmI

Systematic name: S-adenosyl-L-methionine:tRNA (adenine57/adenine58-N1)-methyltransferase

Comments: The enzyme catalyses the formation of N1-methyladenine at two adjacent positions (57 and 58) in the T-loop of certain tRNAs (e.g. tRNAAsp). Methyladenosine at position 57 is an obligatory intermediate for the synthesis of methylinosine, which is commonly found at position 57 of archaeal tRNAs.

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


1. Roovers, M., Wouters, J., Bujnicki, J.M., Tricot, C., Stalon, V., Grosjean, H. and Droogmans, L. A primordial RNA modification enzyme: the case of tRNA (m1A) methyltransferase. Nucleic Acids Res. 32 (2004) 465-476. [PMID: 14739239]

2. Guelorget, A., Roovers, M., Guerineau, V., Barbey, C., Li, X. and Golinelli-Pimpaneau, B. Insights into the hyperthermostability and unusual region-specificity of archaeal Pyrococcus abyssi tRNA m1A57/58 methyltransferase. Nucleic Acids Res. 38 (2010) 6206-6218. [PMID: 20483913]

[EC created 2011 (EC created 1972, part transferred 2011 to EC]

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