Morphology of the intermediate stages in the lamellar to hexagonal lipid phase transition.

Published

Journal Article

The addition of calcium to suspensions of egg phosphatidylcholine and cardiolipin converts multiwalled liposomes to the hexagonal (HII) phase (Rand, R.P., Sengupta, S. (1972) Biochim. Biophys. Acta 255:484-492). We have studied this lamellar to hexagonal phase transition by freeze-fracture, thin-section electron microscopy, and X-ray diffraction and have morphologically characterized the intermediate stages. The first step in the transition involves the invagination and fusion of bilayers, marked by the appearance of lipidic intramembrane particles and "crater-like" indentations, as the large liposomes are converted to smaller flattened and elongated vesicles. The next step is the formation of tightly packed hexagonal arrays of tubules, each tubule being about 11 to 15 nm in diameter. These tubules are filled with fluid and a lipid bilayer forms the wall of each cylinder. Finally this tubular bilayer phase is converted to the hexagonal (HII) phase, where the distance between tubes is 5.5 to 7.5 nm.

Full Text

Duke Authors

Cited Authors

  • Borovjagin, VL; Vergara, JA; McIntosh, TJ

Published Date

  • January 1, 1982

Published In

Volume / Issue

  • 69 / 3

Start / End Page

  • 199 - 212

PubMed ID

  • 7143432

Pubmed Central ID

  • 7143432

Electronic International Standard Serial Number (EISSN)

  • 1432-1424

International Standard Serial Number (ISSN)

  • 0022-2631

Digital Object Identifier (DOI)

  • 10.1007/bf01870399

Language

  • eng