Differences in hydrocarbon chain tilt between hydrated phosphatidylethanolamine and phosphatidylcholine bilayers. A molecular packing model.
Both wide-angle and lamellar x-ray diffraction data are interpreted in terms of a difference in hydrocarbon chain tilt between fully hydrated dipalmitoyl phosphatidylcholine (DPPC) and dipalmitoyl phosphatidylethanolamine (DPPE). Although the hydrocarbon chains of multilayers of DPPC tilt ty approximately 30 degrees relative to the normal to the plane of the bilayer, as previously reported by others, the hydrocarbon chains of DPPE appear to be oriented approximately normal to the plane of the bilayer. It is found that the chain tilt in DPPC bilayers can be reduced by either: (a) adding an n-alkane to the bilayer interiors or (b) adding lanthanum ions to the fluid layers between bilayers. A molecular packing model is presented which accounts for these data. According to this model, DPPC chains tilt because of the size and conformation of the PC polar head group.
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Related Subject Headings
- X-Ray Diffraction
- Pulmonary Surfactants
- Phosphatidylethanolamines
- Models, Structural
- Models, Molecular
- Lipid Bilayers
- Biophysics
- 51 Physical sciences
- 34 Chemical sciences
- 31 Biological sciences
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- X-Ray Diffraction
- Pulmonary Surfactants
- Phosphatidylethanolamines
- Models, Structural
- Models, Molecular
- Lipid Bilayers
- Biophysics
- 51 Physical sciences
- 34 Chemical sciences
- 31 Biological sciences