Ribonucleotide reductase, adenosylcobalamin-dependent (IPR013344)

Short name: RNR_NrdJ/NrdZ

Overlapping homologous superfamilies


Family relationships



Ribonucleotide reductase (also known as ribonucleoside-diphosphate reductase) catalyses the biosynthesis of deoxyribonucleotides from the corresponding ribonucleotides providing the precursors necessary for DNA synthesis. Three main classes of ribonucleotide reductases (RNR) have been discovered that depend on different metal cofactors for the catalytic activity: class I enzymes contain a diiron-oxygen cluster, class II a cobalt containing cobalamin cofactor (vitamin B12), and class III an 4Fe-4S iron-sulfur cluster coupled to S-adenosylmethionine (SAM) [PMID: 15158709].

This entry represents a group of adenosylcobalamin (AdoCbl or coenzymeB12)-dependent ribonucleotide reductases (Class II RNRs) related to the characterised species from Pyrococcus [PMID: 9012808], Thermoplasma [PMID: 8990160], Corynebacterium [PMID: 6986368] and Deinococcus [PMID: 9391052]. RNR's are responsible for the conversion of the ribose sugar of RNA into the deoxyribose sugar of DNA. This is the rate-limiting step of DNA biosynthesis. This model identifies genes in a wide range of deeply branching bacteria. All are structurally related to the class I (non-haem iron-dependent) RNRs. In most species this gene is known as NrdJ, while in mycobacteria it is called NrdZ.

GO terms

Biological Process

GO:0055114 oxidation-reduction process

Molecular Function

GO:0031419 cobalamin binding
GO:0000166 nucleotide binding
GO:0004748 ribonucleoside-diphosphate reductase activity, thioredoxin disulfide as acceptor

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.