Anaerobic microbial redox proteins (PFOR/Fd)

Anaerobic microbial redox proteins, primarily pyruvate:ferredoxin oxidoreductase (PFOR) and ferredoxin, are essential components of the energy metabolism in anaerobic bacteria and certain protozoa (Wikipedia: Pyruvate:ferredoxin oxidoreductase, 2024). These proteins facilitate the oxidative decarboxylation of pyruvate to acetyl-CoA, transferring electrons to low-potential electron carriers like ferredoxin (UniProt: P0C0S1). In a clinical context, these proteins serve as the primary activators for nitroimidazole antibiotics such as metronidazole (StatPearls: Metronidazole, 2023). The low redox potential environment maintained by these proteins allows for the reduction of the drug's nitro group into toxic free radicals, which subsequently cause lethal damage to the microbe's DNA and other cellular components (PubMed: PMC1074380). Because these specific redox pathways are absent in aerobic human cells, they provide a high degree of selective toxicity for treating anaerobic infections (NIH: LiverTox, Metronidazole).

Other names

Pyruvate:ferredoxin oxidoreductase systemPFOR/Ferredoxin systemAnaerobic electron transport proteinsNitroreductase system

These proteins, specifically the PFOR/Ferredoxin system, act as electron donors that reduce the nitro group of nitroimidazole prodrugs into highly reactive, short-lived cytotoxic free radicals (StatPearls: Metronidazole, 2023). These radicals then interact with microbial DNA, causing strand breakage and inhibition of nucleic acid synthesis, leading to cell death (PubMed: PMC1074380).