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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
1.1.1.70 created 1965, deleted 1978 1.1.1.74 created 1972, deleted 1976 1.1.1.89 created 1972, deleted 1976 1.1.1.109 created 1972, deleted 1976 1.1.1.139 created 1972, deleted 1978 1.1.1.155 created 1976, deleted 2004 1.1.1.171 created 1978, deleted 1984 1.1.1.180 created 1983, deleted 1984 1.1.1.182 created 1983, deleted 1990 1.1.1.204 created 1972 as EC 1.2.1.37, transferred 1984 to EC 1.1.1.204, modified 1989, deleted 2004 1.1.1.242 created 1992, deleted 2001 1.1.1.253 created 1999, deleted 2003
1.1.2 With a cytochrome as acceptor
