Enediyne biosynthetic intermediate found

Since the first enediyne was discovered in 1985, scientists have been fascinated by this family of over a dozen natural products. The source of the compounds’ potent anticancer activity is their highly reactive enediyne unit, a double bond flanked by two triple bonds, which cleaves or cross-links genomic DNA by a unique molecular mechanism. Several enediynes are approved drugs or in clinical trials. Bacteria biosynthesize enediynes with multiple reactions that modify β-hydroxyhexaene, a common enediyne precursor produced directly by polyketide synthase enzymes. But many details of these pathways remain unknown. Craig Townsend and Douglas Cohen at Johns Hopkins University recently showed that the two parts of dynemicin A, an anthraquinone group and the enediyne moiety, are produced from β-hydroxyhexaene independently and are then combined to form the natural product. Using pathway product profiling, chemical analysis, and crystallization, Townsend and Cohen have now identified an iodoanthracene derivative as a key intermediate on the pathway to the anthraquinone component (Angew. Chem. Int. Ed. 2018, DOI: 10.1002/anie.201802036). The finding could help lead to better ways to produce enediynes in sufficient quantities for research and clinical use.