NdgRyo, an IclR-like regulator, was selected as the target gene to activate new secondary metabolites in the marine-derived Streptomyces youssoufiensis OUC6819. Inactivation of the ndgRyo gene in S. youssoufiensis OUC6819 led to the accumulation of a new fatty acid amide (1), with an unusual 3-amino-butyl acid as the amine component. Moreover, its parent fatty acid (2) was also discovered both in the wild-type and ΔndgRyo mutant strains, which was for the first time isolated from a natural source. The structures of compounds 1 and 2 were elucidated by combination of LC-MS and NMR spectroscopic analyses. This study demonstrated that the ndgRyo homologs might serve as a target for new compound activation in Streptomyces strains.
Keywords: IclR family regulator; NdgRyo; Streptomyces; fatty acid amide; genome mining.