Functional Reconstitution of Membrane Proteins in Monolayer Liposomes from Bipolar Lipids of Sulfolobus acidocaldarius

Maria Elferink, Janny G. de Wit, Rudy Demel, Arnold J.M. Driessen, Wilhelmus Konings

Research output: Contribution to journalArticleAcademicpeer-review

103 Citations (Scopus)

Abstract

Membranes of Sulfolobus acidocaldarius, an extreme thermophilic archaebacterium, are composed of unusual bipolar lipids. They consist of macrocyclic tetraethers with two polar heads linked by two hydrophobic C40 phytanyl chains which are thought to be arranged as a monolayer in the cytoplasmic membrane. Fractionation of a total lipid-extract from S. acidocaldarius yielded a lipid fraction which forms closed and stable unilamellar liposomes in aqueous media. Beef heart cytochrome c-oxidase could be functionally reconstituted in these liposomes. In the presence of reduced cytochrome c, a protonmotive force (Δp) across the liposomal membrane was generated of up to -92 mV. Upon fusion of these proteoliposomes with membrane vesicles of Lactococcus lactis, the Δp generated by cytochrome c-oxidase activity was capable to drive uphill transport of leucine. Electron microscopic analysis indicated that the tetraether lipids form a single monolayer liposome. The results demonstrate that tetraether lipids of archaebacteria can form a suitable matrix for the function of exogenous membrane proteins originating from a regular lipid bilayer.
Original languageEnglish
Pages (from-to)1375-1381
Number of pages7
JournalThe Journal of Biological Chemistry
Volume267
Issue number2
Publication statusPublished - 15-Jan-1992

Keywords

  • PROTON-MOTIVE FORCE
  • THERMOPHILIC ARCHAEBACTERIA
  • STREPTOCOCCUS-CREMORIS
  • BLACK MEMBRANES
  • ETHER LIPIDS
  • CYTOCHROME-C
  • VESICLES
  • OXIDASE
  • PURIFICATION
  • TEMPERATURE

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