CATH Classification

Domain Context

CATH Clusters

Superfamily Ribonucleotide Reductase, subunit A
Functional Family Ribonucleoside-diphosphate reductase 1 subunit beta

Enzyme Information

1.17.4.1
Ribonucleoside-diphosphate reductase.
based on mapping to UniProt P69924
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 1.1.98.6 and EC 1.17.4.2.

UniProtKB Entries (1)

P69924
RIR2_ECOLI
Escherichia coli K-12
Ribonucleoside-diphosphate reductase 1 subunit beta

PDB Structure

PDB 1MRR
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Substitution of manganese for iron in ribonucleotide reductase from Escherichia coli. Spectroscopic and crystallographic characterization.
Atta, M., Nordlund, P., Aberg, A., Eklund, H., Fontecave, M.
J.Biol.Chem.