Diversity of Polyketide Chains Achieved by Deleting the Tailoring Genes in the Biosynthesis of Ansatrienins

Abstract The ast gene cluster (GenBank accession numbers KF813023.1 and KP284551) was characterized to be responsible for the biosynthesis of ansatrienins in Streptomyces sp. XZQH13, which contains astC , astF1 , and astF2 genes involved in the assembly of the N ‐cyclohexanoyl d ‐alanyl side chain and the hydroxylation of C‐19, respectively. Further to investigating the biosynthetic mechanism of ansatrienins, herein we constructed the mutant strains XZQH13OEΔ astF2 and XZQH13OEΔ astC Δ astF2 . Three new ansatrienin analogues, namely, ansatrienols I–K ( 1 – 3 ), along with trienomycinol ( 4 ) and 3‐ O ‐demethyltrienomycinol ( 5 ), were isolated from the XZQH13OEΔ astC Δ astF2 strain, and trienomycin A ( 6 ) and trienomycin G ( 7 ) were isolated from the XZQH13OEΔ astF2 strain. Their structures were determined by a combination of high‐resolution MS (ESI) and 1D and 2D NMR spectroscopy. Accordingly, a pathway for the biosynthesis of these new ansatrienins was proposed.