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EC 1.1.98.6 Details
show Brenda entryEC number
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,
anaerobic ribonucleoside-triphosphate reductase
Systematic name
ribonucleoside-5′-triphosphate:formate 2′-oxidoreductase
Comment
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).
History
created 2017
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1 Oxidoreductases
1.1.1 With NAD+ or NADP+ as acceptor
1.1.3.1 created 1961, deleted 1984 1.1.3.25 created 1986, deleted 2005 1.1.3.26 created 1989, deleted 2002 1.1.3.31 created 1992, deleted 2003 1.1.3.32 created 1999, deleted 2002 1.1.3.33 created 1999, deleted 2002 1.1.3.34 created 1999, deleted 2002 1.1.3.35 created 1999, deleted 2002 1.1.3.36 created 1999, deleted 2002
