High pressure 2H nuclear magnetic resonance study of the gel phases of dipalmitoylphosphatidylcholine.
The 2H-NMR lineshapes of dipalmitoylphosphatidylcholine perdeuterated in the acyl chains were studied in a 15% dispersion in water as a function of pressure from 1 bar to 5 kbar over the temperature range from 7 degrees C to 75 degrees C. Increasing pressure in the gel state had the same effect as lowering the temperature: the lineshape gradually changed from a motionally averaged to a rigid lattice type spectrum with much of the intensity in the shoulders at +/- 63 kHz. At very high pressures and low temperatures (7 degrees C, 2.5 kbar; 25 degrees C, 5 kbar) even the methyl portion of the spectrum became a rigid lattice type spectrum at +/- 21 kHz. In addition to the liquid crystalline phase, five gel phases were detected. Using different techniques to determine the phase transitions, a general pressure-temperature phase diagram was constructed.
Driscoll
D A
DA
Department of Biochemistry, College of Medicine, University of Illinois, Urbana 61801.
Jonas
J
J
Jonas
A
A
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D003903:Deuterium; D005782:Gels / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011312:Pressure; D013057:Spectrum Analysis / Q000379:methods; D013696:Temperature
D005782:Gels; D008051:Lipid Bilayers; D015060:1,2-Dipalmitoylphosphatidylcholine; D003903:Deuterium