IUBMB Enzyme Nomenclature


Accepted name: tRNA uracil 4-sulfurtransferase

Reaction: ATP + [ThiI sulfur-carrier protein]-S-sulfanyl-L-cysteine + uracil in tRNA + 2 reduced ferredoxin [iron-sulfur] cluster = AMP + diphosphate + 4-thiouracil in tRNA + [ThiI sulfur-carrier protein]-L-cysteine + 2 oxidized ferredoxin [iron-sulfur] cluster

Other name(s): thiI (gene name); transfer ribonucleate sulfurtransferase (ambiguous); RNA sulfurtransferase (ambiguous); ribonucleate sulfurtransferase (ambiguous); transfer RNA sulfurtransferase (ambiguous); transfer RNA thiolase (ambiguous); L-cysteine:tRNA sulfurtransferase (incorrect); tRNA sulfurtransferase (ambiguous)

Systematic name: [ThiI sulfur-carrier protein]-S-sulfanyl-L-cysteine:uracil in tRNA sulfurtransferase

Comments: The enzyme, found in bacteria and archaea, is activated by EC, cysteine desulfurase, which transfers a sulfur atom to an internal L-cysteine residue, forming a cysteine persulfide. The activated enzyme then transfers the sulfur to a uridine in a tRNA chain in a reaction that requires ATP. The enzyme from the bacterium Escherichia coli forms 4-thiouridine only at position 8 of tRNA. The enzyme also participates in the biosynthesis of the thiazole moiety of thiamine, but different domains are involved in the two processes.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9055-57-6


1. Abrell, J.W., Kaufman, E.E. and Lipsett, M.N. The biosynthesis of 4-thiouridylate. Separation and purification of two enzymes in the transfer ribonucleic acid-sulfurtransferase system. J. Biol. Chem. 246 (1971) 294-301. [PMID: 5541999]

2. Hayward, R.S. and Weiss, S.B. RNA thiolase: the enzymatic transfer of sulfur from cysteine to sRNA in Escherichia coli extracts. Proc. Natl. Acad. Sci. USA 55 (1966) 1161-1168. [PMID: 5334200]

3. Lipsett, M.N. and Peterkofsky, A. Enzymatic thiolation of E. coli sRNA. Proc. Natl. Acad. Sci. USA 55 (1966) 1169-1174. [PMID: 5334201]

4. Wong, T., Weiss, S.B., Eliceiri, G.L. and Bryant, J. Ribonucleic acid sulfurtransferase from Bacillus subtilis W168. Sulfuration with β-mercaptopyruvate and properties of the enzyme system. Biochemistry 9 (1970) 2376-2386. [PMID: 4987417]

5. Kambampati, R. and Lauhon, C.T. Evidence for the transfer of sulfane sulfur from IscS to ThiI during the in vitro biosynthesis of 4-thiouridine in Escherichia coli tRNA. J. Biol. Chem. 275 (2000) 10727-10730. [PMID: 10753862]

6. Mueller, E.G., Palenchar, P.M. and Buck, C.J. The role of the cysteine residues of ThiI in the generation of 4-thiouridine in tRNA. J. Biol. Chem. 276 (2001) 33588-33595. [PMID: 11443125]

7. Lauhon, C.T., Erwin, W.M. and Ton, G.N. Substrate specificity for 4-thiouridine modification in Escherichia coli. J. Biol. Chem. 279 (2004) 23022-23029. [PMID: 15037613]

8. Neumann, P., Lakomek, K., Naumann, P.T., Erwin, W.M., Lauhon, C.T. and Ficner, R. Crystal structure of a 4-thiouridine synthetase-RNA complex reveals specificity of tRNA U8 modification. Nucleic Acids Res. 42 (2014) 6673-6685. [PMID: 24705700]

9. Liu, Y., Vinyard, D.J., Reesbeck, M.E., Suzuki, T., Manakongtreecheep, K., Holland, P.L., Brudvig, G.W. and Soll, D. A [3Fe-4S] cluster is required for tRNA thiolation in archaea and eukaryotes. Proc. Natl Acad. Sci. USA 113 (2016) 12703-12708. [PMID: 27791189]

[EC created 1984, modified 2017]

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