J 2021

Lipid Polymorphism of the Subchloroplast-Granum and Stroma Thylakoid Membrane-Particles. II. Structure and Functions

DLOUHY, Ondrej, Vaclav KARLICKY, Rameez ARSHAD, Otto ZSIROS, Ildiko DOMONKOS et. al.

Basic information

Original name

Lipid Polymorphism of the Subchloroplast-Granum and Stroma Thylakoid Membrane-Particles. II. Structure and Functions

Authors

DLOUHY, Ondrej, Vaclav KARLICKY, Rameez ARSHAD, Otto ZSIROS, Ildiko DOMONKOS, Irena KURASOVA, Andras F WACHA, Tomas MOROSINOTTO, Attila BOTA, Roman KOURIL, Vladimir SPUNDA and Gyozo GARAB

Edition

Advances in Fuel Cells, BASEL, Elsevier, 2021, 1752-301X

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10601 Cell biology

Country of publisher

Switzerland

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

UT WoS

000699266100001

Keywords in English

bilayer; chlorophyll fluorescence; cryo-electron-tomography; electron microscopy; membrane energization; membrane networks; non-bilayer lipid phases; SAXS; violaxanthin de-epoxidase

Tags

Tags

International impact, Reviewed
Změněno: 17/10/2024 17:54, Ing. Martina Blahová

Abstract

V originále

In Part I, by using P-31-NMR spectroscopy, we have shown that isolated granum and stroma thylakoid membranes (TMs), in addition to the bilayer, display two isotropic phases and an inverted hexagonal (H-II) phase; saturation transfer experiments and selective effects of lipase and thermal treatments have shown that these phases arise from distinct, yet interconnectable structural entities. To obtain information on the functional roles and origin of the different lipid phases, here we performed spectroscopic measurements and inspected the ultrastructure of these TM fragments. Circular dichroism, 77 K fluorescence emission spectroscopy, and variable chlorophyll-a fluorescence measurements revealed only minor lipase- or thermally induced changes in the photosynthetic machinery. Electrochromic absorbance transients showed that the TM fragments were re-sealed, and the vesicles largely retained their impermeabilities after lipase treatments-in line with the low susceptibility of the bilayer against the same treatment, as reflected by our P-31-NMR spectroscopy. Signatures of H-II-phase could not be discerned with small-angle X-ray scattering-but traces of H-II structures, without long-range order, were found by freeze-fracture electron microscopy (FF-EM) and cryo-electron tomography (CET). EM and CET images also revealed the presence of small vesicles and fusion of membrane particles, which might account for one of the isotropic phases. Interaction of VDE (violaxanthin de-epoxidase, detected by Western blot technique in both membrane fragments) with TM lipids might account for the other isotropic phase. In general, non-bilayer lipids are proposed to play role in the self-assembly of the highly organized yet dynamic TM network in chloroplasts.

Links

90043, large research infrastructures
Name: CIISB