CATH Classification

Domain Context

CATH Clusters

Superfamily 1.10.1650.20
Functional Family Ribonucleoside-diphosphate reductase

Enzyme Information

1.17.4.1
Ribonucleoside-diphosphate reductase.
based on mapping to UniProt Q08698
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)

Q08698
RIR3_SALTY
Salmonella enterica subsp. enterica serovar Typhimurium str. LT2
Ribonucleoside-diphosphate reductase 2 subunit alpha

PDB Structure

PDB 1PEU
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Structure of the large subunit of class Ib ribonucleotide reductase from Salmonella typhimurium and its complexes with allosteric effectors.
Uppsten, M., Farnegardh, M., Jordan, A., Eliasson, R., Eklund, H., Uhlin, U.
J.Mol.Biol.