TolQuin: Quinone biosynthesis, diversity, and evolution across the Tree of Life

• Applicant: Dr. Felix Elling
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms ; Microbial Ecology and Applied Microbiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 569140696

Isoprenoid quinones are lipids that shuttle electrons between enzymes of electron transport chains, thus playing a central role in cellular energy production. Quinones are structurally diverse, with differences in the quinone moiety modulating their redox potential. Low potential quinones are used primarily for anaerobic and microaerobic respiration while high potential quinones are used for aerobic respiration and photosynthesis. The history of their diversification and transition from low to high redox potential is poorly understood, but likely connected to major transitions in the history of life: For example, low potential quinones self-oxidize in the presence of O2 and high potential quinones are thought to have emerged in response to the great oxidation event. Understanding the diversity of quinone biosynthetic pathways is thus likely to bring new insights into the evolution of metabolisms. Recently, our consortium has discovered new pathways of quinone biosynthesis and demonstrated that the evolution of the quinone repertoire is correlated to the adaptation of bacteria to anoxic and oxic environments. Our preliminary results further indicate that many bacterial and archaeal lineages are devoid of known quinones even though their metabolism implies the use of quinones. Further, some lineages produce known quinones but lack the respective pathways, implying the existence of novel pathways. Finally, our preliminary application of novel lipidomics workflows suggests that a wide diversity of quinones from cultured organisms and environmental samples awaits discovery. Research gaps are thus 1) the elucidation of new pathways for known quinones, 2) discovering novel quinones and their biosynthetic pathways, and 3) resolving the evolution of quinones biosynthetic pathways. We believe that characterizing quinone diversity, biosynthetic pathways and their evolution across the tree of life will provide a new perspective on the evolution and diversification of metabolisms, such as transitions between anaerobic and aerobic metabolisms in the context of Earth’s redox evolution. To this end, we propose to, 1) develop lipidomics-based techniques to discover novel quinones across bacterial and archaeal diversity, using cultures of target organisms and environmental samples; 2) improve current sequence-based annotation of quinone pathways using structural information to detect remote candidate genes, and biochemically and genetically characterize missing or incomplete biosynthetic pathways in bacteria and archaea; 3) investigate the eco-physiological and evolutionary significance of quinone diversity and acquisition. Our combined expertise in biochemistry, biogeochemistry, lipidomics, molecular evolution and microbiology, will ensure the success of ToLQuin, and allow us to obtain a new view of quinone diversity across the tree of life in link to major metabolic transitions.

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partner: Dr. Sophie Abby