Structural analysis of hydrated egg lecithin and cholesterol bilayers II. Neutron diffraction

doi:10.1016/S0022-2836(76)80068-X

Journal of Molecular Biology

Volume 100, Issue 3, 25 January 1976, Pages 359-378

https://doi.org/10.1016/S0022-2836(76)80068-X Get rights and content

Lamellar neutron diffraction was measured from hydrated multilayers of a mixture of egg lecithin and cholesterol oriented on glass substrates. One-dimensional Fourier profiles of the coherent scattering amplitude density across the bilayer repeat units were calculated for multilayers hydrated with both H₂O and D₂O using phase assignments which were directly determined. The D₂O−H₂O difference Fourier profiles show that the amounts of water across the repeat units are greatest between the polar groups of adjacent bilayers, and are flat in the hydrocarbon region within the experimental accuracy of ± 0·3 water molecules/lecithin molecule. The observed distribution of water can only be accounted for if the Zwitterionic dipole of the phosphatidyl choline group is oriented in the plane of the bilayer. The position of the hydroxyl group of the cholesterol molecule was determined by deuterium labelling of the adjacent carbon atom and use of a direct scaling method for comparing data from labelled and unlabelled samples. The deuterium label was found to be at the position of the glyceryl-fatty acid ester bonds, and the cholesterol molecule is therefore immersed in the hydrocarbon region of the bilayer.

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^†: Present address: Materials Physics Division, Atomic Energy Research Establishment, Harwell, Didcot, Oxfordshire, England.

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Journal of Molecular Biology

Structural analysis of hydrated egg lecithin and cholesterol bilayers II. Neutron diffraction

Biochim. Biophys. Acta

Biochim. Biophys. Acta

J. Mol. Biol.

Biochim. Biophys. Acta

J. Lipid Res.

J. Biol. Chem.

Chem. Phys. Lipids

J. Mol. Biol.

J. Theoret. Biol.

Biochim. Biophys. Acta

Progr. Biophys. Mol. Biol.

Biochim. Biophys. Acta

Biochim. Biophys. Acta

Biochim. Biophys. Acta

Biophys. J.

biochim. Biophys. Acta

Chem. Phys. Lipids

J. Lipid Res.

J. Lipid Res.

Biochim. Biophys. Acta

J. Mol. Biol.

Acta Crystallogr.

Acta Crystallogr.

Eur. J. Biochem.

Nature

Experientia

Circulation