Targeted Discovery of Pentaketide Ansamycin Aminoansamycins A-G.

Ansamycins are a class of macrolactams with diverse bioactivities, characterized by the unique 3-amino-5-hydroxybenzoic acid moiety. In this study, the ansamycin gene cluster aas in Streptomyces sp. S35 was activated by the constitutive coexpression of two pathway-specific regulator genes aas1 and aas10, and seven novel pentaketide ansamycin aminoansamycins A-G (1-7) were identified. Compound 4 with better antiproliferative activity indicated that the anthranilate analogues are probably promising building blocks for the production of unnatural ansamycins with improved activity.