This model represents a small clade of ribonucleoside-diphosphate reductase, alpha chains which are sufficiently divergent from the usual Class I RNR alpha chains (NrdE or NrdA, TIGR02506) as to warrant their own model. The genes from Thermus thermophilus, Dichelobacter and Salinibacter are adjacent to the usual RNR beta chain. [Purines, pyrimidines, nucleosides, and nucleotides, 2'-Deoxyribonucleotide metabolism]
Jiyao W et al.(2023). "The conserved domain database in 2023.",