This model represents a group of adenosylcobalamin(B12)-dependent ribonucleotide reductases (Class II RNRs) related to the characterized species from Pyrococcus, Thermoplasma, Corynebacterium, and Deinococcus. 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-heme iron dependent) RNRs. In most species this gene is known as NrdJ, while in mycobacteria it is called NrdZ. [Purines, pyrimidines, nucleosides, and nucleotides, 2'-Deoxyribonucleotide metabolism]
Jiyao W et al.(2023). "The conserved domain database in 2023.",