This model represents the oxygen-sensitive (anaerobic, class III) ribonucleotide reductase. The mechanism of the enzyme involves a glycine-centered radical, a C-terminal zinc binding site, and a set of conserved active site cysteines and asparagines. This enzyme requires an activating component, NrdG, a radical-SAM domain containing enzyme (TIGR02491). Together the two form an alpha-2/beta-2 heterodimer. [Purines, pyrimidines, nucleosides, and nucleotides, 2'-Deoxyribonucleotide metabolism]