IUBMB Enzyme Nomenclature


Accepted name: ribonucleoside-triphosphate reductase (formate)

Reaction: ribonucleoside 5'-triphosphate + formate = 2'-deoxyribonucleoside 5'-triphosphate + CO2 + H2O

Other name(s): nrdD (gene name); class III ribonucleoside-triphosphate reductase; anaerobic ribonucleotide reductase; anaerobic ribonucleoside-triphosphate reductase

Systematic name: ribonucleoside-5'-triphosphate:formate 2'-oxidoreductase

Comments: The enzyme, which is expressed in the bacterium Escherichia coli during anaerobic growth, contains an iron sulfur center. The active form of the enzyme contains an oxygen-sensitive glycyl radical that is generated by the activating enzyme NrdG via chemistry involving S-adenosylmethionine (SAM) and a [4Fe-4S] cluster. The glycyl radical is involved in generation of a transient thiyl radical on a cysteine residue, which attacks the substrate, forming a ribonucleotide 3'-radical, followed by water loss to form a ketyl radical. The ketyl radical gains an electron from a cysteine residue and a proton from formic acid, forming 3'-keto-deoxyribonucleotide and generating a thiosulfuranyl radical bridge between methionine and cysteine residues. Oxidation of formate by the thiosulfuranyl radical results in the release of CO2 and regeneration of the thiyl radical. cf. EC, ribonucleoside-diphosphate reductase and EC, ribonucleoside-triphosphate reductase (thioredoxin).

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


1. Eliasson, R., Pontis, E., Fontecave, M., Gerez, C., Harder, J., Jornvall, H., Krook, M. and Reichard, P. Characterization of components of the anaerobic ribonucleotide reductase system from Escherichia coli. J. Biol. Chem. 267 (1992) 25541-25547. [PMID: 1460049]

2. Mulliez, E., Fontecave, M., Gaillard, J. and Reichard, P. An iron-sulfur center and a free radical in the active anaerobic ribonucleotide reductase of Escherichia coli. J. Biol. Chem. 268 (1993) 2296-2299. [PMID: 8381402]

3. Mulliez, E., Ollagnier, S., Fontecave, M., Eliasson, R. and Reichard, P. Formate is the hydrogen donor for the anaerobic ribonucleotide reductase from Escherichia coli. Proc. Natl. Acad. Sci. USA 92 (1995) 8759-8762. [PMID: 7568012]

4. Ollagnier, S., Mulliez, E., Schmidt, P.P., Eliasson, R., Gaillard, J., Deronzier, C., Bergman, T., Graslund, A., Reichard, P. and Fontecave, M. Activation of the anaerobic ribonucleotide reductase from Escherichia coli. The essential role of the iron-sulfur center for S-adenosylmethionine reduction. J. Biol. Chem. 272 (1997) 24216-24223. [PMID: 9305874]

5. Wei, Y., Mathies, G., Yokoyama, K., Chen, J., Griffin, R.G. and Stubbe, J. A chemically competent thiosulfuranyl radical on the Escherichia coli class III ribonucleotide reductase. J. Am. Chem. Soc. 136 (2014) 9001-9013. [PMID: 24827372]

[EC created 2017]

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