Betain-Lipide in euKaryoten

• Antragsteller: Professor Dr. Emanuel Schneck
• Fachliche Zuordnung: Biochemie und Biophysik der Pflanzen ; Biophysik ; Stoffwechselphysiologie, Biochemie und Genetik der Mikroorganismen
• Förderung: Förderung von 2018 bis 2024
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 406647862

• Erstellungsjahr: 2023

Zusammenfassung der Projektergebnisse

During their evolution, microorganisms and plants have developed strategies to replace phospholipids with phosphorous-free analogues under conditions of phosphate starvation. It has, however, been unknown to which extent these substitutes share the same physicochemical characteristics and therefore leave biological processes unaffected. In the BLinK project, we have performed comparative physicochemical characterizations of three important classes of phospholipids and their presumed phosphorous-free substitutes: (i) PC lipids vs. DGTS, (ii) PE lipids vs. OL, and (iii) PG lipids vs. SQDG. PC lipids and DGTS were investigated most comprehensively. We found that DGTS bilayers in the fluid phase are about half a nanometer thicker than PC lipid bilayers, have higher bending rigidity, a stronger membrane-membrane repulsion, and a greater tendency than PC lipid bilayers to coexist in the gel and fluid phase. They exhibit similar thermodynamics of lateral compression but a smaller chain tilt and higher lateral packing, which is consistent with the formation of thicker bilayers. At the same time, our phylogenetic analyses (see section 2.2) revealed that the evolution of DGTS biosynthesis splits between marine and freshwater organisms, suggesting a different selection pressure acting on marine and freshwater environments. OL and PE lipids were found to behave very differently in the investigated single-component model systems with saturated tails. OL can form a molecular superlattice involving the uncharged protonation state, which surprisingly persists over a wide pH range. However, biological membranes are multicomponent systems with mainly unsaturated lipids that form predominantly liquid-like phases and therefore rather inhibit the formation of highly ordered structures. Under such fluid conditions the differences between OL and PE lipids may be largely mitigated, so that replacement of PE lipids by OL under phosphate-starvation may nevertheless be biologically tolerable. Despite chemically very different headgroups, PG lipids and SQDG were found to have similar physicochemical properties with regard to bilayer thickness, bending rigidity, and membranemembrane interactions. SQDG can thus indeed be considered a good substitute for PG under phosphate-starvation. Overall, the results of this project constitute a solid physicochemical basis for further biochemical and biological interpretations and we have provided valuable insights into the aspects that are relevant for the substitution of one lipid type by another one.

Projektbezogene Publikationen (Auswahl)

• Biophysical properties of glycerolipids and their impact on membrane architecture and biology. Advances in Botanical Research, 1-57. Elsevier.
  S. Bolik; B. Demé & J. Jouhet
  
• pH-Dependent physicochemical properties of ornithine lipid in mono-and bilayers. Physical Chemistry Chemical Physics, 24(37), 22778-22791.
  Mukhina, Tetiana; Pabst, Georg; Ruysschaert, Jean-Marie; Brezesinski, Gerald & Schneck, Emanuel
  
• Phase behavior and miscibility in lipid monolayers containing glycolipids. Journal of Colloid and Interface Science, 615, 786-796.
  Mukhina, Tetiana; Brezesinski, Gerald; Shen, Chen & Schneck, Emanuel
  
• Phase Behavior and Miscibility in Two-Component Glycolipid Monolayers. The Journal of Physical Chemistry B, 126(34), 6464-6471.
  Mukhina, Tetiana; Brezesinski, Gerald & Schneck, Emanuel
  
• Sulfoquinovosyldiacylglycerol and phosphatidylglycerol bilayers share biophysical properties and are good mutual substitutes in photosynthetic membranes. Biochimica et Biophysica Acta (BBA) -Biomembranes, 1864(12), 184037.
  Bolik, Stéphanie; Albrieux, Catherine; Schneck, Emanuel; Demé, Bruno & Jouhet, Juliette
  
• The Complete Phase Diagram of Monolayers of Enantiomeric N-Stearoyl-threonine Mixtures with Preferred Heterochiral Interactions. Langmuir, 38(41), 12521-12529.
  Mukhina, Tetiana; Richter, Lars; Vollhardt, Dieter; Brezesinski, Gerald & Schneck, Emanuel
  
• Lipid bilayer properties potentially contributed to the evolutionary disappearance of betaine lipids in seed plants. BMC Biology, 21(1).
  Bolik, Stéphanie; Schlaich, Alexander; Mukhina, Tetiana; Amato, Alberto; Bastien, Olivier; Schneck, Emanuel; Demé, Bruno & Jouhet, Juliette