CATH Classification

Domain Context

CATH Clusters

Superfamily 3.20.70.20
Functional Family Ribonucleoside-diphosphate reductase large subunit

Enzyme Information

1.17.4.1
Ribonucleoside-diphosphate reductase.
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 diferric-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 radical on a cysteine residue, which attacks the substrate, forming a ribonucleotide 3'-radical, followed by water loss to form a ketyl 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 3R1R
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
Binding of allosteric effectors to ribonucleotide reductase protein R1: reduction of active-site cysteines promotes substrate binding.
Eriksson, M., Uhlin, U., Ramaswamy, S., Ekberg, M., Regnstrom, K., Sjoberg, B.M., Eklund, H.
Structure