| Summary: | Atratumycin is a cyclodepsipeptide with activity against <i>Mycobacteria tuberculosis</i> isolated from deep-sea derived <i>Streptomyces atratus</i> SCSIO ZH16NS-80S. Analysis of the atratumycin biosynthetic gene cluster (<i>atr</i>) revealed that its biosynthesis is regulated by multiple factors, including two LuxR regulatory genes (<i>atr1</i> and <i>atr2</i>), two ABC transporter genes (<i>atr29</i> and <i>atr30</i>) and one <i>Streptomyces</i> antibiotic regulatory gene (<i>atr32</i>). In this work, three regulatory and two transporter genes were unambiguously determined to provide positive, negative and self-protective roles during biosynthesis of atratumycin through bioinformatic analyses, gene inactivations and <i>trans</i>-complementation studies. Notably, an unusual <i>Streptomyces</i> antibiotic regulatory protein Atr32 was characterized as a negative regulator; the function of Atr32 is distinct from previous studies. Five over-expression mutant strains were constructed by rational application of the regulatory and transporter genes; the resulting strains produced significantly improved titers of atratumycin that were ca. 1.7−2.3 fold greater than wild-type (WT) producer. Furthermore, the atratumycin gene cluster was successfully expressed in <i>Streptomyces coelicolor</i> M1154, thus paving the way for the transfer and recombination of large DNA fragments. Overall, this finding sets the stage for understanding the unique biosynthesis of pharmaceutically important atratumycin and lays the foundation for generating anti-tuberculosis lead compounds possessing novel structures.
|
|---|