IUBMB Enzyme Nomenclature


Accepted name: tRNA-5-methyluridine54 2-sulfurtransferase

Reaction: ATP + [TtuB sulfur-carrier protein]-Gly-NH-CH2-C(O)SH + 5-methyuracil54 in tRNA + H2O = AMP + diphosphate + 5-methyl-2-thiouracil54 in tRNA + [TtuB sulfur-carrier protein]-Gly-Gly

Other name(s): TtuA

Systematic name: [TtuB sulfur-carrier protein]-Gly-NH-CH2-C(O)SH:tRNA (5-methyluridine54-2-O)-sulfurtransferase

Comments: The enzyme, found in thermophilic bacteria such as Thermus thermophilus and archaea such as Pyrococcus horikoshii, modifies the ribothymidine (5-methyluridine) residue at position 54 of tRNAs. Contains zinc and an [4Fe-4S] cluster.

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


1. Shigi, N., Sakaguchi, Y., Suzuki, T. and Watanabe, K. Identification of two tRNA thiolation genes required for cell growth at extremely high temperatures. J. Biol. Chem. 281 (2006) 14296-14306. [PMID: 16547008]

2. Shigi, N., Suzuki, T., Terada, T., Shirouzu, M., Yokoyama, S. and Watanabe, K. Temperature-dependent biosynthesis of 2-thioribothymidine of Thermus thermophilus tRNA. J. Biol. Chem. 281 (2006) 2104-2113. [PMID: 16317006]

3. Nakagawa, H., Kuratani, M., Goto-Ito, S., Ito, T., Katsura, K., Terada, T., Shirouzu, M., Sekine, S., Shigi, N. and Yokoyama, S. Crystallographic and mutational studies on the tRNA thiouridine synthetase TtuA. Proteins 81 (2013) 1232-1244. [PMID: 23444054]

4. Chen, M., Narai, S., Omura, N., Shigi, N., Chimnaronk, S., Tanaka, Y. and Yao, M. Crystallographic study of the 2-thioribothymidine-synthetic complex TtuA-TtuB from Thermus thermophilus. Acta Crystallogr. F Struct. Biol. Commun. 72 (2016) 777-781. [PMID: 27710943]

[EC created 2017]

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