CATH Domain 5cnuA02
|3.20.70||Anaerobic Ribonucleotide-triphosphate Reductase Large Chain|
based on mapping to UniProt P00452
2'-deoxyribonucleoside diphosphate + thioredoxin disulfide + H(2)O = ribonucleoside diphosphate + thioredoxin.
-!- This enzyme is responsible for the de novo conversion of ribonucleoside diphosphates into deoxyribonucleoside diphosphates, which are essential for DNA synthesis and repair. -!- There are three types of this enzyme differing in their cofactors. -!- Class Ia enzymes contain a diiron(III)-tyrosyl radical, class Ib enzymes contain a dimanganese-tyrosyl radical, and class II enzymes contain adenosylcobalamin. -!- In all cases the cofactors are 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 (alpha-oxoalkyl) radical. -!- The ketyl radical is reduced to 3'-keto-deoxynucleotide concomitant with formation of a disulfide anion radical between two cysteine residues. -!- A proton-coupled electron-transfer from the disulfide radical to the substrate generates a 3'-deoxynucleotide radical, and the the final product is formed when the hydrogen atom that was initially removed from the 3'-position of the nucleotide by the thiyl radical is returned to the same position. -!- The disulfide bridge is reduced by the action of thioredoxin. -!- Cf. EC 220.127.116.11 and EC 18.104.22.168.
UniProtKB Entries (1)
Escherichia coli K-12
Ribonucleoside-diphosphate reductase 1 subunit beta
Molecular basis for allosteric specificity regulation in class Ia ribonucleotide reductase from Escherichia coli.