Streptomyces aureorectus DSM 41692 and Streptomyces virens DSM 41465 are producers of the antibiotic nucleocidin and 4′-fluoroadenosine is identified as a co-product

Genome homology and the presence of a putative biosynthetic gene cluster identified Streptomyces aureorectus DSM 41692 and Streptomyces virens DSM 41465 as candidate producers of the antibiotic nucleocidin 1. Indeed when these bacterial strains were cultured in a medium supplemented with fluoride (4 mM) they each produced nucleocidin 1 and the previously identified 4′-fluoro-3′-O-β-glucosylated adenosine 2 and its sulfamylated derivative 3. In both of these cases 4′-fluoroadenosine 9 is also identified as a natural product although it has never been observed during fermentations of Streptomyces calvus, the original source of nucleocidin 1. The identity of 4′-fluoroadenosine 9 was confirmed by a total synthesis as well as by its in vitro enzymatic conversion to metabolite 2 using the glucosyl transferase enzyme, NucGT.