Structural aspects of pressure effects on infrared spectra of mixed-chain phosphatidylcholine assemblies in D/sub 2/O
The barotropic behavior of D/sub 2/O dispersions of 1-stearoyl-2-caproyl-sn-glycero-3-phosphocholine, C(18):C(10)PC, a highly asymmetric phospholipid in which the length of the fully extended acyl chain at the sn-1 position of the glycerol backbone is twice as long as that at the sn-2 position, has been investigated by high-pressure Fourier transform infrared spectroscopy. This asymmetric phosphatidylcholine bilayer at room temperature displays a pressure-induced phase transition corresponding to the liquid-crystalline----gel phase transition at 1.4 kbar. A conformational ordering of the lipid acyl chains is observed to take place abruptly at the transition pressure of 1.4 kbar. However, the lamellar lipid molecules and their acyl chains remain to be orientationally disordered in the gel phase until the applied pressure reaches 5.5 kbar. In the gel phase of fully hydrated C(18):C(10)PC, the asymmetric lipid molecules assemble into mixed interdigitated bilayers with perpendicular orientation of the zigzag planes among neighboring acyl chains. The role of excess water played in the interchain structure and the behavior of excess water and bound water under high pressure are also discussed.
- Research Organization:
- National Research Council of Canada, Ottawa, Ontario
- OSTI ID:
- 6075860
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 28:3; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
DEUTERIUM
ESTERS
FOURIER TRANSFORMATION
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFRARED SPECTRA
INTEGRAL TRANSFORMATIONS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPIDS
MOLECULAR STRUCTURE
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHOLIPIDS
SPECTRA
SPECTROPHOTOMETRY
STABLE ISOTOPES
TRACER TECHNIQUES
TRANSFORMATIONS
WATER