Catalyzes the final step in the biosynthesis of the sesquiterpenoid antibiotic pentalenolactone by mediating the oxidative rearrangement of pentalenolactone F to pentalenolactone. 2 H(+) + O2 + pentalenolactone F + 2 reduced [2Fe-2S]-[ferredoxin] = 2 H2O + 2 oxidized [2Fe-2S]-[ferredoxin] + pentalenolactone kcat is 8.8 min(-1) with pentalenolactone F as substrate. Antibiotic biosynthesis; pentalenolactone biosynthesis. Accumulation of the precursor pentalenolactone F and lack of production of pentalenolactone. Belongs to the cytochrome P450 family.