A new paradigm for the regulation of A40926B0 biosynthesis

Dalbavancin is a novel glycopeptide antibiotic with activity against a broad range of Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). A40926B0 is the direct precursor of dalbavancin, but the regulatory mechanisms underlying its biosynthesis are not well understood. Additionally, the presence of seven homologs leads to significant metabolic burden, affecting both production and purity of A40926B0. To further reveal the transcriptional regulatory mechanism of A40926B0 biosynthesis in N. gerenzanensis L70, this study employed multiple strategies to explore the regulatory network of its biosynthesis from both intracluster and extracluster aspects. WblA regulates gene expression within and outside the biosynthetic gene cluster (BGC), impacting multiple biosynthetic pathways, and Dbv3, a key regulator in the A40926B0 cluster, positively influences biosynthesis. Using a bottom-up (DNA to protein) regulator mining strategy with the key intra-cluster regulator Dbv3, it was determined that GlnR is also involved in the regulation of secondary metabolism, while BkdR regulates precursor supply. By constructing the combination of GlnR, BkdR and Dbv3 together with the WblA deletion, the regulatory network of A40926B0 was reconstructed, resulting in a 92 % improvement in purity of A40926B0. The objective of this study is to elucidate the regulatory mechanisms governing A40926B0 biosynthesis by constructing a comprehensive, multidimensional model of its regulatory network. The findings of this study serve to enhance our comprehension of A40926B0 biosynthesis and furnish insights into broader strategies for enhancing the production of other natural products and secondary metabolites in industrial microbiology.