Deletion of the side chain assembly reveals diverse post-PKS modifications in the biosynthesis of ansatrienins†
Abstract
Seven new ansatrienin-type ansamycins, namely, ansatrienols B–H (1–7), along with four known ones (8–11), were isolated from the strain Streptomyces sp. XZQH13OEΔastC constructed by deleting the astC gene responsible for the assembly of the N-cyclohexanoyl D-alanyl side chain. Their structures were determined by analysis of the 1D and 2D NMR spectroscopic data and high-resolution ESIMS. This study revealed the diverse post-PKS modifications during the biosynthesis of ansatrienins.