X-Ray Studies on Phospholipid Bilayers, in. Structure and Morphology of L-a-Dilaurylphosphatidylethanolamine (DLPE)

Phospholipid, Bilayer, X-Ray Diffraction, Morphology, D ilaurylphosphatidylethanolamine, Membrane Powder samples and oriented films of the synthetic phospholipid L-a-dilaurylphosphatidylethanolamine (DLPE) were studied by X-ray diffraction over a wide range of hydration. Only small differences were found between the unit cell dimensions of DLPE powder and orientedfilm specimens. These dimensions did not vary appreciably with hydration. In the multilayer DLPE structure, the molecules pack with polar groups parallel to the bilayer plane and hydro­ carbon chains perpendicular to it. Examination of oriented films by scanning electron microscopy gave information on the surface morphology. Complementary data on the lamellar packing of the molecules and the average thickness of the bilayers was provided by thin-section and shadow-cast preparations studied by transmission electron microscopy.