<p> This entry represents a group of adenosylcobalamin (AdoCbl or coenzymeB12)-dependent ribonucleotide reductases (Class II RNRs) related to the characterised species from Pyrococcus [<cite idref="PUB00020749"/>], Thermoplasma [<cite idref="PUB00020776"/>], Corynebacterium [<cite idref="PUB00016697"/>] and Deinococcus [<cite idref="PUB00020792"/>]. 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.</p> Ribonucleoside-diphosphate reductase, adenosylcobalamin-dependent