title: Hexagonal packing of lipid acyl chains and membrane plasticity.
abstract: Electron microscope and electron diffraction observations on microcrystals of pure lipids (a phosphatidylethanolamine, two phosphatidylcholines, a phosphatidic acid, and a galactocerebroside) reveal an extreme flexibility of lipid layers when the acyl chains are hexagonally packed (d100 = 4.17 A). This is corroborated by similar observations on wet bilayers of a lecithin. It is shown that more "crystalline" polymethylene packings do not impart such plasticity to lipid layers and are therefore an unsuitable structural matrix for dynamic biological membranes.
mesh_terms: D002554:Cerebrosides; D003461:Crystallography; D008563:Membrane Lipids; D008567:Membranes, Artificial; D008854:Microscopy, Electron; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010743:Phospholipids
chemical_list: D002554:Cerebrosides; D008563:Membrane Lipids; D008567:Membranes, Artificial; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010743:Phospholipids