Biochemistry, Biophysics, and Structural Biology Commons^™

Lateral Phase Separations In Binary Mixtures Of Phospholipids Having Different Charges And Different Crystalline Structures, Elizabeth Luna, Harden Mcconnell

Elizabeth J. Luna

Synthetic dipalmitoyl phosphatidylserine exhibits a sharp chain-melting transition temperature at 51 degrees C as judged by partitioning of the spin label 2,2,6,6-tetramethylpiperidine-1-oxyl. Phase diagrams representing lateral phase separations in binary mixtures of dipalmitoyl phosphatidylserine with dipalmitoyl phosphatidylcholine as well as with dimyristoyl phosphatidylcholine are derived from paramagnetic resonance determinations of 2,2,6,6,-tetramethylpiperidine-1-oxyl partitioning, freeze-fracture electron microscopic studies and theoretical arguments that limit the general form of acceptable phase diagrams. The reported phase diagrams are the first to describe binary mixtures in which one lipid is charged and the second lipid uncharged. These phase diagrams also are the first to include the …