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Evolutionary biochemistry of lipid membranes

membrane,terpenoid,biomarker,biochemistry,steroid,hopanoid

Theme 4: Microbial and Biogeochemical Evolution through Time > Session 4e: Microbial Lipid Biomarkers and Their Isotopes in Environment, Biology, and Evolution

Lipid biomarkers are invaluable molecular fossils that enable us to understand ancient ecosystems and dynamic interactions between life and Earth. Lipid biomarkers are derived from lipid membranes - an indispensable platform for cellular life to generate energy and perform multitudes of fundamental cellular processes, including respiration, photosynthesis and signal transduction. Chemically speaking, lipid membranes create a unique environment that enables the transformation of hydrophobic substrates that cannot be present in the cytosol and certain forms of biochemistry can indeed be performed only in membranes. Hence, the evolution of lipid membranes as a distinctive chemical reactive space has a special meaning in the history of biochemistry. Interestingly, many biomarkers are ultimate products of such membrane biochemistry. Examples include the radical SAM-based alkyl chain coupling during archaeal membrane biosynthesis (Zeng et al., 2022) and the stereoselective carbon-carbon coupling cascade during polycyclic terpenoid biosynthesis such as hopanoids and steroids (Christianson, 2017). In turn, generated lipids alter the biophysical property of host membranes and eventually the fitness of host organisms. The most well-known example is the role of steroids in the maintenance of modern eukaryotic cells (Hoshino, 2024). Hence, membrane biochemistry served among key molecular driving forces behind the evolution of life. Parent biomolecules of lipid biomarkers are therefore not just chemotaxonomic markers, but also active participants themselves that supported the diversification of life. This presentation explores a perspective of studying lipid biomarkers as a tool to examine the evolutionary aspect of membrane biochemistry, utilizing some latest and also previous studies, and understand the universal feature of lipid membranes as an evolvable chemical space (Schneider et al., 2023).



References:

Zeng Z., ChennH., Yang H., Chen Y., Yangn W., Feng X., Pei H., Welander P. V., 2022. Identification of a protein responsible for the synthesis of archaeal membrane-spanning GDGT lipids. Nature Communications 13:154.

Christianson D., 2017. Structural and Chemical Biology of Terpenoid Cyclases. Chemical Review 117, 11570–11648.

Hoshino Y., 2024. Terpenoids and membrane dynamics evolution, Frontiers in Ecology and Evolution, 12, 1345733.

Schneider A., Ruppert J., Lystbæk T. B., Bastian S., Hauer B., 2023. Expanding the Cation Cage: Squalene-Hopene Cyclase-Mediated Enantioselective Semipinacol Rearrangement. ACS Catalysis 13, 1946–1951.