Ribonucleotide reductase class III (RNR class III)

Ribonucleotide reductase class III catalyzes the conversion of ribonucleotides to deoxyribonucleotides, providing the building blocks required for DNA synthesis in anaerobic bacteria[7]. This enzyme is a glycyl radical protein that operates under strictly anaerobic conditions, using formate or similar electron donors and is oxygen-sensitive. It is essential for bacterial proliferation and is absent in human cells, positioning it as a potential selective antibacterial drug target. There are other supporting enzymes and systems involved in bacterial DNA synthesis, such as DNA polymerases, helicases, and regulatory proteins (like DnaA for origin unwinding[1]), but RNR class III serves as the canonical, defining enzyme for anaerobic deoxyribonucleotide production[7].

Other names

RNR-IIIAnaerobic ribonucleotide reductasenrdD/nrdG (gene names)Class III ribonucleotide reductase

Inhibition leads to depletion of deoxyribonucleotide pools, halting DNA synthesis and cell division[7]. Some inhibitors irreversibly inactivate the glycyl radical essential for class III enzyme function (theoretically applies).