One Metabolite, Two Pathways: Convergence of Polypropionate Biosynthesis in Fungi and Marine Molluscs

Structural similarity or even the identity of polyketide compounds does not necessarily imply unique biosynthesis. Feeding experiments with a C-13 labeled precursor establish that the C-3 units in 7-methyl-cyercene-1 (1) are derived from intact propionate in the marine mollusc Ercolania funerea. The same compound in the terrestrial fungus Leptosphaeria maculans/Phoma lingam is synthesized by an acetate/SAM pathway thus proving for the first time metabolic convergence of polyketide biosynthesis in eukaryotes. Traditional H-1-C-13 NMR correlation spectroscopy has been successfully applied to estimate C-13 incorporation in biosynthetic experiments.