A new role for coenzyme F₄₂₀ in aflatoxin reduction by soil mycobacteria

Hepatotoxic aflatoxins have found a worthy adversary in two new families of bacterial oxidoreductases. These enzymes use the reduced coenzyme F₄₂₀ to initiate the degradation of furanocoumarin compounds, including the major mycotoxin products of Aspergillus flavus. Along with pyridoxal 5'-phosphate synthases and aryl nitroreductases, these proteins form a large and versatile superfamily of flavin and deazaflavin-dependent oxidoreductases. F₄₂₀-dependent members of this family appear to share a common mechanism of hydride transfer from the reduced, low-potential deazaflavin to the electron-deficient ring systems of their substrates.