ISSN:
1059-910X
Keywords:
Lipid monolayers
;
Lipid bilayers
;
Electron diffraction
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Natural Sciences in General
Notes:
Lipid monolayer is a half leaflet model for lipid bilayer, which forms the basis of biological membranes. Within a certain range of surface area per molecule of phospholipid monolayers at the air-water interface, where the compressibility was nearly infinite, two phases with different molecular packings were observable by fluorscence microscopy. Mixed-phase monolayers of L-1,2-dipalmitoyl-N-monomethyl-3-phosphatidylethanolamine [DP(Me)PE] or L-1,2-dipalmitoyl-N-dimethyl-3-phosphatidyl-ethanolamine [DP(Me)2PE] were deposited on marker grids coated with Formvar films. The molecular organization in the dark and bright fluorescent areas on the grids was investigated by low dose, selected area electron diffraction. Sharp reflection arcs, at a spacing of 4.2Å and arranged in a hexagon pattern, were detected from dark domains of both lipids. A diffuse reflection ring at a spacing of 4.6Å was derived from the bright background areas. Diffraction patterns were obtained from neighboring areas along selected dark domains of both lipids. The orientations of diffraction patterns from areas along smooth and curving boundries of DP(Me)2PE domains were found to turn with the boundaries. In the branching domains of DP(Me)PE, the orientations of diffraction patterns indicated that the branches were formed by twinning. Electron diffraction thus provides an unique way to sample the local molecular packing order and orientation within individual domains in phospholipid monolayers. © 1994 Wiley-Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jemt.1070270511
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