The transmembrane distribution of galactolipids in chloroplast thylakoids is universal in a wide variety of temperate climate plants

Abstract

The transmembrane distribution of monogalactosyldiacylglycerol and digalactosyldiacylglycerol was determined in chloroplast thylakoids from a range of temperate climate plants. These plants included dicotyledons, monocotyledons, C16:3 and C18:3 plants and herbicide-resistant species. In all the thylakoids examined monogalactosyldiacylglycerol was enriched in the outer leaflet (53-65%) while digalactosyldiacylglycerol was highly enriched in the inner leaflet (78-90%). The non-bilayer forming monogalactosyldiacylglycerol represented 55-81% of the total acyl lipids of the outer monolayer. The relative acyl lipid composition of both leaflets of the thylakoid membrane indicates that the lamellar structure is strongly favored in the inner monolayer, whereas the outer one presents a metastable character which allows the probable coexistence of both lamellar and non-lamellar phases. The consequence of this asymmetry for the stability and function of the thylakoid membrane is discussed.

Glycerolipid transfer for the building of membranes in plant cells

“…The above-mentioned scramblase-like plant protein may play a role in affecting the plasma membrane asymmetry. The thylakoids show a marked asymmetry in the transversal distribution of the lipids with an enrichment of the outer leaflet in MGDG and PG while DGDG and SQDG are essentially confined to the inner leaflet [23].…”

Plant Lipidomics: Signalling and Analytical Strategies

“…Over 80-90 % of polar lipids are accumulated in plastid envelope and thylakoid membrane (Dorne et al 1990 ). The outer leafl et of the thylakoid membrane is enriched with monogalactosyldiacylglycerol (MGDG) and phosphatidylglycerol (PG), whereas the inner leafl et consist of digalactosyldiacylglycerol (DGDG), this variation in the distribution was due to stable asymmetric transmembrane of thylakoid membrane occurring in a variety of monocot and dicot species (Giroud and Siegenthaler 1988 ;Joyard et al 1991 ;Rawyler et al 1987 ;Siegenthaler and Giroud 1986 ).…”

Isolation and purification of intralamellar vesicles from Lemna minor L. chloroplasts

“…However, the galactolipid composition of IV could be associated to the composition of one of the thylakoid monolayers. The transmembrane distribution of galactolipids in thylakoids has been extensively reviewed (Sprague & Staehelin, 1984;Rawyler et al, 1987). On average, for any higher plant, the molar ratio of DGG/DDG is around 1-4 for the inner monolayer and above 4 for the outer monolayer (Rawyler et al, 1987).…”

“…The transmembrane distribution of galactolipids in thylakoids has been extensively reviewed (Sprague & Staehelin, 1984;Rawyler et al, 1987). On average, for any higher plant, the molar ratio of DGG/DDG is around 1-4 for the inner monolayer and above 4 for the outer monolayer (Rawyler et al, 1987). Consequently, based on their galactolipid ratio, IV appear structurally more similar to the outer monolayer than to the inner monolayer of thylakoid membranes.…”