IUBMB Enzyme Nomenclature


Accepted name: tRNAIle-lysidine synthase

Reaction: [tRNAIle2]-cytidine34 + L-lysine + ATP = [tRNAIle2]-lysidine34 + AMP + diphosphate + H2O

Glossary: lysidine = N6-(4-amino-1-β-D-ribofuranosylpyrimidin-2-ylidene)-L-lysine

Other name(s): TilS; mesJ (gene name); yacA (gene name); isoleucine-specific transfer ribonucleate lysidine synthetase; tRNAIle-lysidine synthetase

Systematic name: L-lysine:[tRNAIle2]-cytidine34 ligase (AMP-forming)

Comments: The bacterial enzyme modifies the wobble base of the CAU anticodon of tRNAIle at the oxo group in position 2 of cytidine34. This modification determines both codon and amino acid specificities of tRNAIle.

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


1. Ikeuchi, Y., Soma, A., Ote, T., Kato, J., Sekine, Y. and Suzuki, T. molecular mechanism of lysidine synthesis that determines tRNA identity and codon recognition. Mol. Cell 19 (2005) 235-246. [PMID: 16039592]

2. Salowe, S.P., Wiltsie, J., Hawkins, J.C. and Sonatore, L.M. The catalytic flexibility of tRNAIle-lysidine synthetase can generate alternative tRNA substrates for isoleucyl-tRNA synthetase. J. Biol. Chem. 284 (2009) 9656-9662. [PMID: 19233850]

3. Nakanishi, K., Fukai, S., Ikeuchi, Y., Soma, A., Sekine, Y., Suzuki, T. and Nureki, O. Structural basis for lysidine formation by ATP pyrophosphatase accompanied by a lysine-specific loop and a tRNA-recognition domain. Proc. Natl. Acad. Sci. USA 102 (2005) 7487-7492. [PMID: 15894617]

4. Soma, A., Ikeuchi, Y., Kanemasa, S., Kobayashi, K., Ogasawara, N., Ote, T., Kato, J., Watanabe, K., Sekine, Y. and Suzuki, T. An RNA-modifying enzyme that governs both the codon and amino acid specificities of isoleucine tRNA. Mol. Cell 12 (2003) 689-698. [PMID: 14527414]

5. Nakanishi, K., Bonnefond, L., Kimura, S., Suzuki, T., Ishitani, R. and Nureki, O. Structural basis for translational fidelity ensured by transfer RNA lysidine synthetase. Nature 461 (2009) 1144-1148. [PMID: 19847269]

[EC created 2011]

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