Phosphatidyl-Glycerol in Mixtures with Positively Charged Amphiphiles: A 2H- and 31P-NMR Study of the Phase Behaviour and Headgroup Structure
The thermotropic behaviour of membranes composed of 1-palmitoy 1-2-oleoyl-sn3-phosphatidyl-glycerol (POPG) and dimethyl-dihexadecyl-ammonium bromide (DHAB) was investigated with differential scanning calorimetry and 2H- and 31Pnmr spectroscopy. The main transition temperature, Tm , from the gel state to the liquid-crystalline state (l.c.) showed a local maximum around 40 mole % DHAB in the membranes. With nmr spectroscopy we also detected non-bilayer properties of the system. Both the DSC scans and the phase diagram of the system are presented.
KeywordsDifferential Scanning Calorimetry Quadrupole Splitting Liquid Crystalline State Phosphatidyl Glycerol Thermotropic Behaviour
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