1.14.11.36 physiological function enzyme deletion mutants accumulate pentalenolactone D but are blocked in production of pentalenolactone as well as the precursors pentalenolactones E and F. Analysis of the gene cluster responsible for pentalenolactone synthesis. Reaction starts with the flavin-dependent Baeyer-Villiger oxidation of 1-deoxy-11-oxopentalenic acid to pentalenolactone D followed by the two-stage Fe2+-alpha-ketoglutarate-dependent oxidation to pentalenolactones E and F, catalyzed by the enzyme, PntD. Incubation of PntD with its natural substrate neopentalenolactone D gives a mixture of neopentalenolactone E and its derived hydrolysis product, methyl (1R,6aR)-6a-acetyl-1-(2-methoxy-2-oxoethyl)-5,5-dimethyl-1,3a,4,5,6,6a-hexahydropentalene-2-carboxylate -, 718892 1.14.11.36 physiological function enzyme deletion mutants accumulate pentalenolactone D but are blocked in production of pentalenolactone as well as the precursors pentalenolactones E and F. Analysis of the gene cluster responsible for pentalenolactone synthesis. Reaction starts with the flavin-dependent Baeyer-Villiger oxidation of 1-deoxy-11-oxopentalenic acid to pentalenolactone D followed by the two-stage Fe2+-alpha-ketoglutarate-dependent oxidation to pentalenolactones E and F, catalyzed by the enzyme, PtlD. Incubation of PtlD with its natural substrate neopentalenolactone D gives a mixture of neopentalenolactone E and its derived hydrolysis product, methyl (1R,6aR)-6a-acetyl-1-(2-methoxy-2-oxoethyl)-5,5-dimethyl-1,3a,4,5,6,6a-hexahydropentalene-2-carboxylate -, 718892