The Enzyme Database

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EC 1.1.98.6     
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
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 (1-amino-2-oxoethan-1-yl) 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 (sulfanyl) radical on a cysteine residue, which attacks the substrate, forming a ribonucleotide 3′-radical, followed by water loss to form a ketyl (α-oxoalkyl) 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 (1λ4-disulfan-1-yl) 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 1.17.4.1, ribonucleoside-diphosphate reductase and EC 1.17.4.2, ribonucleoside-triphosphate reductase (thioredoxin).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
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 1.1.98.6 created 2017]
 
 


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