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Lipid Polymorphism of the Subchloroplast—Granum and Stroma Thylakoid Membrane—Particles. I.$ ^{31}$P-NMR Spectroscopy
| Content Provider | MDPI |
|---|---|
| Author | Ond, řej Dlouhý Primo, ž Šket Vladim, ír Špunda Karlický, Václav Javornik, Uroš Zsiros, Ottó Plavec, Janez Garab, Győző |
| Copyright Year | 2021 |
| Description | Build-up of the energized state of thylakoid membranes and the synthesis of ATP are warranted by organizing their bulk lipids into a bilayer. However, the major lipid species of these membranes, monogalactosyldiacylglycerol, is a non-bilayer lipid. It has also been documented that fully functional thylakoid membranes, in addition to the bilayer, contain an inverted hexagonal $(H_{II}$) phase and two isotropic phases. To shed light on the origin of these non-lamellar phases, we performed$ ^{31}$P-NMR spectroscopy experiments on sub-chloroplast particles of spinach: stacked, granum and unstacked, stroma thylakoid membranes. These membranes exhibited similar lipid polymorphism as the whole thylakoids. Saturation transfer experiments, applying saturating pulses at characteristic frequencies at 5 °C, provided evidence for distinct lipid phases—with component spectra very similar to those derived from mathematical deconvolution of the$ ^{31}$P-NMR spectra. Wheat-germ lipase treatment of samples selectively eliminated the phases exhibiting sharp isotropic peaks, suggesting easier accessibility of these lipids compared to the bilayer and the $H_{II}$ phases. Gradually increasing lipid exchanges were observed between the bilayer and the two isotropic phases upon gradually elevating the temperature from 5 to 35 °C, suggesting close connections between these lipid phases. Data concerning the identity and structural and functional roles of different lipid phases will be presented in the accompanying paper. |
| Starting Page | 2354 |
| e-ISSN | 20734409 |
| DOI | 10.3390/cells10092354 |
| Journal | Cells |
| Issue Number | 9 |
| Volume Number | 10 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2021-09-08 |
| Access Restriction | Open |
| Subject Keyword | Cells Plant Sciences 31p-nmr Bilayer Membrane Dem—dynamic Exchange Model Grana Hii Phase Isotropic Phase Non-bilayer Lipids Non-lamellar Lipid Phases Thylakoid Membranes Structural Flexibility |
| Content Type | Text |
| Resource Type | Article |
