Activation and Identification of NC‐1: A Cryptic Cyclodepsipeptide from Red Soil‐Derived Streptomyces sp. FXJ1.172

Abstract

Genome sequence analysis of a lasalocid‐producing strain, Streptomyces sp. FXJ1.172, which was isolated from red soil, indicated its great untapped biosynthetic potential for novel secondary metabolites. A lasalocid‐null mutant Streptomyces sp. FXJ1.172ΔlodS, was then constructed to make way for the cryptic biosynthetic pathways. Consequently, a novel cyclodepsipeptide, named NC‐1, was activated and isolated from the lasalocid abolished mutant strain cultivated in glucose‐yeast extract‐malt extract (GYM) medium supplemented with ferric ion. The planar‐ and stereo‐structures of NC‐1 were elucidated based on detailed analyses of MS, NMR, and single‐crystal X‐ray diffraction data, revealing it as the first reported cyclodepsipeptide that is epoxidized at adjacent carbon atoms of the cinnamoyl fatty acid side chain. In assays of antimicrobial activity, NC‐1 exhibited moderate inhibition effects against Mycobacterium bovis bacille Calmette–Guérin (BCG).