Self-assembly of large, ordered lamellae from non-bilayer lipids and integral membrane proteins in vitro

Ilian Simidjiev, Svetla Stoylova, Heinz Amenitsch, Tamás Jávorfi, László Mustárdy, Peter Laggner, Andreas Holzenburg, Gyozo Garab

Research output: Contribution to journalArticlepeer-review

104 Scopus citations

Abstract

In many biological membranes, the major lipids are 'non-bilayer lipids,' which in purified form cannot be arranged in a lamellar structure. The structural and functional roles of these lipids are poorly understood. This work demonstrates that the in vitro association of the two main components of a membrane, the non-bilayer lipid monogalactosyldiacylglycerol (MGDG) and the chlorophyll-a/b light-harvesting antenna protein of photosystem II (LHCII) of pea thylakoids, leads to the formation of large, ordered lamellar structures: (i) thin-section electron microscopy and circular dichroism spectroscopy reveal that the addition of MGDG induces the transformation of isolated, disordered macroaggregates of LHCII into stacked lamellar aggregates with a long-range chiral order of the complexes; (ii) small-angle x-ray scattering discloses that LHCII perturbs the structure of the pure lipid and destroys the inverted hexagonal phase; and (iii) an analysis of electron micrographs of negatively stained 2D crystals indicates that in MGDG-LHCII the complexes are found in an ordered macroarray. It is proposed that, by limiting the space available for MGDG in the macroaggregate, LHCII inhibits formation of the inverted hexagonal phase of lipids; in thylakoids, a spatial limitation is likely to be imposed by the high concentration of membrane-associated proteins.

Original languageEnglish (US)
Pages (from-to)1473-1476
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume97
Issue number4
DOIs
StatePublished - Feb 15 2000

Keywords

  • Chloroplast thylakoid membranes
  • Circular dichroism
  • Electron microscopy
  • Light-harvesting complex
  • Lipid-protein interactions

ASJC Scopus subject areas

  • General

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