Streptomyces bacteria are a valuable source of natural products, many of which are used in the clinic or in biotechnology. In our search for novel antibiotics we discovered lugdunomycin, a natural... Show moreStreptomyces bacteria are a valuable source of natural products, many of which are used in the clinic or in biotechnology. In our search for novel antibiotics we discovered lugdunomycin, a natural product with a highly complex chemical architecture that is produced by Streptomyces sp. QL37. It is derived from the angucyclines, a well-known class of molecules known for their antibacterial and anticancer activities. Though angucyclines are produced in high quantities under most conditions, lugdunomycin is produced in minimal amounts. This thesis describes novel insights into the transcriptional control of the lugdunomycin biosynthetic gene cluster and into the lugdunomycin biosynthesis pathway. These insights may be applied to improve the yield of lugdunomycin and expand the chemical diversity of angucyclines. Using molecular biology, bioinformatic approaches and omics studies, such as metabolomics and transcriptomics, we have characterized the lugdunomycin biosynthetic gene cluster, the regulatory genes (lugRI–lugRV) required for transcriptional activation of the cluster, and the oxygenase genes (lugOI–lugOV) that play a key role in the different chemical rearrangements of the angucyclines. Furthermore, this thesis contains a detailed review of the regulatory network that controls antibiotic production in Actinobacteria. Show less
Streptomyces present a valuable platform for natural product discovery. Lugdunomycin is a novel angucycline-derived polyketide from Streptomyces sp QL37, with unprecedented skeleton and... Show moreStreptomyces present a valuable platform for natural product discovery. Lugdunomycin is a novel angucycline-derived polyketide from Streptomyces sp QL37, with unprecedented skeleton and antimicrobial activity. This dissertation covers the research on the biosynthesis of this novel antibiotic and the developmental biology of Streptomyces. The data in this thesis have provided important new insights into the puzzle of lugdunomycin biosynthesis and the sporulation-specific cell division of Streptomyces. By means of molecular biology, structural biology, biochemical, chemical and bioinformatics approaches, we have uncovered the potential functions of the key enzymes, especially those encoded oxygenases (LugOI-LugOV) in lugdunomycin biosynthesis. Furthermore, we extensively studied the role of SsgB in Streptomyces development, that led us to the discovery of longitudinal cell division that support the predominant role of SsgB in the accurate positioning of the division site and the placement of the Z-ring. Show less
