Studies on the Biosynthesis of Spirostaphylotrichin A

Incorporation of ¹⁴C-labelled acetate and amino acids as well as of 1-¹³C]-, 2-¹³C]-, and 1,2-¹³C₂] acetate, L -methyl¹³C] methionine, 2,3-¹³C₂] succinate, and L -2,3-¹³C₂] aspartate into spirostaphylotrichin A ( 1 ) by Staphylotrichum coccosporum demonstrates that the building blocks of 1 are 5 units of acetate/malonate, 1 unit of methionine, and a C₄-dicarboxylic acid. The latter is most likely aspartate and derived from the citric-acid cycle. Using 2-¹³C, 2-²H₃] acetate as a precursor, the starter unit of the polyketide chain was identified.