Discovery and Characterization of Novel Tetrodecamycins

Antibiotics are one of the most important groups of drugs ever discovered. In addition to their clinical use, these small molecules have also been essential for understanding the molecular details of numerous fundamental biological processes. As a result, the discovery and characterization of novel small molecules is of extraordinary value to both society and science. Streptomyces sp. strain WAC04657 is a wild-isolate bacterium that produces an antibiotic activity against multi-drug resistant Staphylococcus aureus. I purified the responsible molecule and characterized it as 13-deoxytetrodecamycin, a new antibiotic belonging to the tetrodecamycin-group of molecules. To study the biosynthesis of this molecule, I sequenced the genome of WAC04657 and, using bioinformatic methods, identified the biosynthetic gene cluster. I named this cluster the ted cluster. To confirm that these genes were responsible for producing 13-deoxytetrodecamycin, I genetically manipulated genes within the cluster with the goal of making an overproducer strain and a non-producer strain. In addition to affecting the expression of 13-deoxytetrodecamycin, these mutants show alterations in the expression of four other molecules. I purified two of these and solved their structures. One I identified as the known molecule tetrodecamycin, while the second was a novel molecule that I named W5.9. A search of public genome sequences revealed that the ted cluster was also found in three other bacteria: Streptomyces atroolivaceus, Streptomyces globisporus, and Streptomyces sp. LaPpAH-202. By genetically manipulating the ted cluster in S. atroolivaceus and S. globisporus, I was able to confirm that these bacteria were also producers of tetrodecamycin â group molecules. Specifically, they produced tetrodecamycin and dihydrotetrodecamycin. In summary, the work reported in this thesis describes the discovery of a novel antibiotic as well the biosynthetic gene cluster responsible for producing it. Future work will focus on assessing the therapeutic potential of the tetrodecamycin-group molecules and identifying their mechanism of action.Ph.D