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Structural Entities Associated with Different Lipid Phases of Plant Thylakoid Membranes—Selective Susceptibilities to Different Lipases and Proteases.

Authors :
Dlouhý, Ondřej
Karlický, Václav
Javornik, Uroš
Kurasová, Irena
Zsiros, Ottó
Šket, Primož
Kanna, Sai Divya
Böde, Kinga
Večeřová, Kristýna
Urban, Otmar
Gasanoff, Edward S.
Plavec, Janez
Špunda, Vladimír
Ughy, Bettina
Garab, Győző
Source :
Cells (2073-4409); Sep2022, Vol. 11 Issue 17, p2681, 18p
Publication Year :
2022

Abstract

It is well established that plant thylakoid membranes (TMs), in addition to a bilayer, contain two isotropic lipid phases and an inverted hexagonal (H<subscript>II</subscript>) phase. To elucidate the origin of non-bilayer lipid phases, we recorded the <superscript>31</superscript>P-NMR spectra of isolated spinach plastoglobuli and TMs and tested their susceptibilities to lipases and proteases; the structural and functional characteristics of TMs were monitored using biophysical techniques and CN-PAGE. Phospholipase-A1 gradually destroyed all <superscript>31</superscript>P-NMR-detectable lipid phases of isolated TMs, but the weak signal of isolated plastoglobuli was not affected. Parallel with the destabilization of their lamellar phase, TMs lost their impermeability; other effects, mainly on Photosystem-II, lagged behind the destruction of the original phases. Wheat-germ lipase selectively eliminated the isotropic phases but exerted little or no effect on the structural and functional parameters of TMs—indicating that the isotropic phases are located outside the protein-rich regions and might be involved in membrane fusion. Trypsin and Proteinase K selectively suppressed the H<subscript>II</subscript> phase—suggesting that a large fraction of TM lipids encapsulate stroma-side proteins or polypeptides. We conclude that—in line with the Dynamic Exchange Model—the non-bilayer lipid phases of TMs are found in subdomains separated from but interconnected with the bilayer accommodating the main components of the photosynthetic machinery. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
20734409
Volume :
11
Issue :
17
Database :
Complementary Index
Journal :
Cells (2073-4409)
Publication Type :
Academic Journal
Accession number :
159006426
Full Text :
https://doi.org/10.3390/cells11172681