X-ray structure determination of fully hydrated L alpha phase dipalmitoylphosphatidylcholine bilayers.

Bilayer form factors obtained from x-ray scattering data taken with high instrumental resolution are reported for multilamellar vesicles of L alpha phase lipid bilayers of dipalmitoylphosphatidylcholine at 50 degrees C under varying osmotic pressure. Artifacts in the magnitudes of the form factors due to liquid crystalline fluctuations have been eliminated by using modified Caillé theory. The Caillé fluctuation parameter eta 1 increases systematically with increasing lamellar D spacing and this explains why some higher order peaks are unobservable for the larger D spacings. The corrected form factors fall on one smooth continuous transform F(q); this shows that the bilayer does not change shape as D decreases from 67.2 A (fully hydrated) to 60.9 A. The distance between headgroup peaks is obtained from Fourier reconstruction of samples with four orders of diffraction and from electron density models that use 38 independent form factors. By combining these results with previous gel phase results, area AF per lipid molecule and other structural quantities are obtained for the fluid L alpha phase. Comparison with results that we derived from previous neutron diffraction data is excellent, and we conclude from diffraction studies that AF = 62.9 +/- 1.3 A2, which is in excellent agreement with a previous estimate from NMR data.

[1]  Sun,et al.  Critical Fluctuations in Membranes. , 1995, Physical review letters.

[2]  M. Klein,et al.  Constant pressure and temperature molecular dynamics simulation of a fully hydrated liquid crystal phase dipalmitoylphosphatidylcholine bilayer. , 1995, Biophysical journal.

[3]  C. Shull,et al.  Neutron Diffraction Studies , 1948 .

[4]  J. Torbet,et al.  X-ray diffraction studies of lecithin bilayers. , 1976, Journal of theoretical biology.

[5]  T. Irving,et al.  Small-angle x-ray scattering from lipid bilayers is well described by modified Caillé theory but not by paracrystalline theory. , 1996, Biophysical journal.

[6]  D. Engelman,et al.  Lipid bilayer thickness varies linearly with acyl chain length in fluid phosphatidylcholine vesicles. , 1983, Journal of molecular biology.

[7]  Suter,et al.  Theory of the structure factor of lipid bilayers. , 1994, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[8]  John F. Nagle,et al.  Theory of the Main Lipid Bilayer Phase Transition , 1980 .

[9]  R. Pastor,et al.  Computer simulation of liquid/liquid interfaces. II. Surface tension-area dependence of a bilayer and monolayer , 1995 .

[10]  T. McIntosh,et al.  Area per molecule and distribution of water in fully hydrated dilauroylphosphatidylethanolamine bilayers. , 1986, Biochemistry.

[11]  B P Schoenborn,et al.  Neutron diffraction studies on the location of water in lecithin bilayer model membranes. , 1975, Proceedings of the National Academy of Sciences of the United States of America.

[12]  Bernard R. Brooks,et al.  Computer simulation of liquid/liquid interfaces. I. Theory and application to octane/water , 1995 .

[13]  J. Seelig.  Deuterium magnetic resonance: theory and application to lipid membranes , 1977, Quarterly Reviews of Biophysics.

[14]  J. Nagle,et al.  Area/lipid of bilayers from NMR. , 1993, Biophysical journal.

[15]  G Büldt,et al.  Neutron diffraction studies on phosphatidylcholine model membranes. I. Head group conformation. , 1979, Journal of molecular biology.

[16]  T. McIntosh,et al.  Hydration force and bilayer deformation: a reevaluation. , 1986, Biochemistry.

[17]  L. J. Lis,et al.  Interactions between neutral phospholipid bilayer membranes. , 1982, Biophysical journal.

[18]  E. Jakobsson,et al.  Incorporation of surface tension into molecular dynamics simulation of an interface: a fluid phase lipid bilayer membrane. , 1995, Biophysical journal.

[19]  R. Suter,et al.  Measurement of chain tilt angle in fully hydrated bilayers of gel phase lecithins. , 1993, Biophysical journal.

[20]  Douglas J. Tobias,et al.  Constant Pressure and Temperature Molecular Dynamics Simulations of Crystals of the Lecithin Fragments: Glycerylphosphorylcholine and Dilauroylglycerol , 1995 .

[21]  V. Parsegian,et al.  Hydration forces between phospholipid bilayers , 1989 .

[22]  G Büldt,et al.  Neutron diffraction studies on phosphatidylcholine model membranes. II. Chain conformation and segmental disorder. , 1979, Journal of molecular biology.

[23]  W. R. Lieb,et al.  The structure of lipid bilayers and the effects of general anaesthetics. An x-ray and neutron diffraction study. , 1979, Journal of molecular biology.

[24]  J. Nagle,et al.  Relations for lipid bilayers. Connection of electron density profiles to other structural quantities. , 1989, Biophysical journal.

[25]  S H White,et al.  Structure of a fluid dioleoylphosphatidylcholine bilayer determined by joint refinement of x-ray and neutron diffraction data. III. Complete structure. , 1992, Biophysical journal.

[26]  J. Nagle,et al.  Specific volumes of lipids in fully hydrated bilayer dispersions. , 1988, Biochimica et biophysica acta.

[27]  J. Nagle,et al.  Lecithin bilayers. Density measurement and molecular interactions. , 1978, Biophysical journal.

[28]  Zhang,et al.  Order and disorder in fully hydrated unoriented bilayers of gel-phase dipalmitoylphosphatidylcholine. , 1994, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[29]  J. Nagle,et al.  Structure of fully hydrated bilayer dispersions. , 1988, Biochimica et biophysica acta.

[30]  C. R. Worthington.  The interpretation of low-angle X-ray data from planar and concentric multilayered structures. The use of one-dimensional electron density strip models. , 1969, Biophysical journal.

[31]  C. Safinya,et al.  A synchrotron X-ray study of competing undulation and electrostatic interlayer interactions in fluid multimembrane lyotropic phases , 1988 .

[32]  V. Luzzati,et al.  Structure and polymorphism of the hydrocarbon chains of lipids: a study of lecithin-water phases. , 1973, Journal of molecular biology.

[33]  R. Suter,et al.  Structure of the fully hydrated gel phase of dipalmitoylphosphatidylcholine. , 1989, Biophysical journal.

[34]  Structure and polymorphism of the hydrocarbon chains of lipids: a study of lecithin-water phases. , 1973 .

[35]  G. Degovics,et al.  Small-angle X-ray scattering and electron microscopy of crude dispersions of swelling lipids and the influence of the morphology on the repeat distance , 1988 .

[36]  T. McIntosh,et al.  Direct structure determination of multilayered membrane-type systems which contain fluid layers. , 1973, Biophysical journal.