The role of lipids in the global organization of thylakoid membranes of higher plants

The first steps of photosynthesis (capturing of light and conversion of light energy into chemical energy) occur in the thylakoid membrane of the chloroplasts. It consists for 75% of membrane proteins and 25% of lipid molecules. In this thesis the global properties of the lipids in the thylakoid membrane are studied with a variety of spectroscopic techniques. Special attention is paid to the lipid packing, phase behavior and membrane permeability, as well as the role of the lipids in structural rearrangements and the overall organization of the membrane. The presented results reveal heterogeneity in the packing of the bulk lipid molecules and the participation of the lipids in both bilayer and non-bilayer structures. It is demonstrated that the lipid mixture has an active role in the lateral arrangement of the protein complexes, the formation of macrodomains and their thermal stability and indirectly in the excitation energy trapping by the photosynthetic complexes. This work provides a basis for further future investigations of the properties of the thylakoid lipid matrix and of the lipid-protein interactions in thylakoid membranes and their relevance for different functions of the membrane.