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Increased thermal stability of photosystem II and the macro-organization of thylakoid membranes, induced by co-solutes, associated with changes in the lipid-phase behaviour of thylakoid membranes
- Source :
- Photosynthetica. 56:254-264
- Publication Year :
- 2018
- Publisher :
- Institute of Experimental Botany, 2018.
-
Abstract
- The principal function of the thylakoid membrane depends on the integrity of the lipid bilayer, yet almost half of the thylakoid lipids are of non-bilayer-forming type, whose exact functions are not fully understood. Non-bilayer lipids can be extruded from the membrane in the presence of high concentrations of co-solutes. We applied 2 M sucrose to induce lipid phase separation in isolated thylakoid membranes, following consequent structural and physiological effects. Circular dichroism spectroscopy indicated significant changes in the chiral macro-arrangement of the pigment–protein complexes, which were reversed after washing out the co-solute. Similarly, merocyanine-540 fluorescence suggested reversible changes in the lipid phases. The PSII function, as tested by chlorophyll fluorescence induction transients and time-resolved fluorescence, was almost unaffected. However, the presence of sucrose dramatically increased the PSII thermostability, which can partly be explained by a direct osmolyte effect and partly by the lipid phase separation stabilizing the stacked membrane.
- Subjects :
- 0106 biological sciences
0301 basic medicine
Circular dichroism
Photosystem II
Physiology
Chemistry
food and beverages
Plant Science
01 natural sciences
03 medical and health sciences
030104 developmental biology
Membrane
Osmolyte
Phase (matter)
Thylakoid
Biophysics
lipids (amino acids, peptides, and proteins)
Lipid bilayer
Chlorophyll fluorescence
010606 plant biology & botany
Subjects
Details
- ISSN :
- 15739058 and 03003604
- Volume :
- 56
- Database :
- OpenAIRE
- Journal :
- Photosynthetica
- Accession number :
- edsair.doi...........2c1ff9199b3f4b5a468b460a41d7c28d