title: Thiocyanate and bromide ions influence the bilayer structural parameters of phosphatidylcholine bilayers.
abstract: The influence of monovalent cations and anions on the structural parameters of dipalmitoylphosphatidylcholine (DPPC) bilayers was examined at 25 degrees C using X-ray diffraction. It was shown that monovalent salts, in general, have little effect on lipid packing within the bilayer. However, fully hydrated DPPC bilayers in 1 M KSCN pack in an interdigitated acyl chain phase. This is the first observation of an ion-induced interdigitated bilayer phase in a zwitterionic lipid. In addition, gel state DPPC bilayers in 1 M KBr imbibe approx. 10 A more solvent than bilayers in water. The influence of these same salts on the phase transitions of DPPC bilayers was also examined using high-resolution differential scanning calorimetry. These results are discussed in terms of ion-induced changes in solvent and solvent/bilayer structure.
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000378:metabolism*; D001965:Bromides / Q000378:metabolism*; D008051:Lipid Bilayers; D011188:Potassium / Q000378:metabolism*; D017680:Potassium Compounds; D012492:Salts / Q000378:metabolism; D013816:Thermodynamics; D013861:Thiocyanates / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D001965:Bromides; D008051:Lipid Bilayers; D017680:Potassium Compounds; D012492:Salts; D013861:Thiocyanates; D015060:1,2-Dipalmitoylphosphatidylcholine; C039004:potassium bromide; D011188:Potassium; C009941:potassium thiocyanate