The biosynthesis and enzymology of complex rubromycin and tropone marine bacterial natural products

• Applicant: Professor Dr. Robin Teufel
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 439507043

• Final Report Year: 2024

Final Report Abstract

The goal of the project was to investigate key steps in the biosynthesic pathways of bacterial rubromycin and tropone natural products, which are compounds with interesting antibiotic and/or anticancer activities. Despite the shortened period, several key goals could be achieved. The biosynthesis of the complex spiroketal pharmacophore of the rubromycin-type aromatic polyketides could be elucidated in detail, involving a set of consecutively acting enzymes that drastically rearrange the backbone of an advanced pathway intermediate. Although some intermediates proved to be too labile and short-lived to allow their full structural elucidation, a plausible biosynthetic route could be proposed. More detailed mechanistic and structural studies of the central enzyme of this process were conducted in a follow-up work, which shed light onto how the enzyme controls the complex steps. In the course of these studies, an unanticipated regulation mechanism of one of the involved enzymes was discovered, which is the subject of current studies. In a comparable effort, late steps in the biosynthesis of so-called tropones were investigated, which play crucial roles in numerous symbiotic interactions, e.g. as protective antibiotics in corals or sponges. Again, a central step could be unraveled, which involved an unusual enzyme that catalyzes several distinct reactions and eventually produces a highly reactive product. The enzymatic product is likely converted into the mature tropone natural products, which is subject to further investigation. Overall, these studies provide insights into how structurally complex bioactive metabolites are produced in bacteria and set the stage, e.g., for subsequent efforts aiming to generate novel bioactive compounds by utilizing the herein characterized biosynthetic enzymes.

Publications

• A Flavoprotein Dioxygenase Steers Bacterial Tropone Biosynthesis via Coenzyme A-Ester Oxygenolysis and Ring Epoxidation. Journal of the American Chemical Society, 143(27), 10413-10421.
  Duan, Ying; Toplak, Marina; Hou, Anwei; Brock, Nelson L.; Dickschat, Jeroen S. & Teufel, Robin
  
• Catalytic Control of Spiroketal Formation in Rubromycin Polyketide Biosynthesis. Angewandte Chemie International Edition, 60(52), 26960-26970.
  Toplak, Marina; Saleem‐Batcha, Raspudin; Piel, Jörn & Teufel, Robin
  
• Enzymatic spiroketal formation via oxidative rearrangement of pentangular polyketides. Nature Communications, 12(1).
  Frensch, Britta; Lechtenberg, Thorsten; Kather, Michel; Yunt, Zeynep; Betschart, Martin; Kammerer, Bernd; Lüdeke, Steffen; Müller, Michael; Piel, Jörn & Teufel, Robin
  
• The devil is in the details: The chemical basis and mechanistic versatility of flavoprotein monooxygenases. Archives of Biochemistry and Biophysics, 698, 108732.
  Toplak, Marina; Matthews, Arne & Teufel, Robin
  
• Three Rings to Rule Them All: How Versatile Flavoenzymes Orchestrate the Structural Diversification of Natural Products. Biochemistry, 61(2), 47-56.
  Toplak, Marina & Teufel, Robin
  
• An acetyltransferase controls the metabolic flux in rubromycin polyketide biosynthesis by direct modulation of redox tailoring enzymes. Chemical Science, 13(24), 7157-7164.
  Toplak, Marina; Nagel, Adelheid; Frensch, Britta; Lechtenberg, Thorsten & Teufel, Robin
  
• Ungewöhnliche Flavoenzyme steuern die Bildung von Troponen in Bakterien. BIOspektrum, 28(4), 394-396.
  Toplak, Marina; Höing, Lars & Teufel, Robin