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Thermomechanical and transition properties of dimyristoylphosphatidylcholine/cholesterol bilayers.

Publication ,  Journal Article
Needham, D; McIntosh, TJ; Evans, E
Published in: Biochemistry
June 28, 1988

Mixtures of dimyristoylphosphatidylcholine (DMPC) and cholesterol (Chol) have been used to examine the effects of cholesterol on the chain crystallization transitions and thermomechanical properties in phospholipid bilayer membranes. The mechanical properties--elastic moduli and level of tension at membrane rupture--were derived from micropipet pressurization of giant single-walled vesicles. Also, the micropipet method allowed temperature-dependent area transitions to be measured at constant membrane tension. X-ray diffraction measurements were made on selected lipid/cholesterol mixtures. Wide-angle patterns and electron density profiles were used to measure bilayer thickness as an indication of chain tilt and fluidity. Vesicle area versus temperature plots showed that the main acyl chain crystallization transition of DMPC broadened and shifted to higher temperatures. Both above and below the broad transition, the elastic area compressibility modulus, K, was greatly increased with cholesterol addition. The value for the 1:1 DMPC/Chol complex was found to be approximately 700 dyn/cm, comparable to that for DMPC in the L beta' phase. However, for all concentrations above 12.5 mol % (which was weakly solid), vesicle bilayers behaved as surface liquids with no surface shear rigidity even at temperatures well below the DMPC phase transition. Area changes over the broadened transitions were reduced by cholesterol and disappeared with the addition of 50 mol % to leave the thermal area expansivity at 1.3 X 10(-3)/degrees C. These area changes are consistent with separate formation of a 1:1 DMPC/Chol complex that does not condense plus residual free lipid and lipid loosely associated with the 1:1 complex that freezes normally.(ABSTRACT TRUNCATED AT 250 WORDS)

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Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

June 28, 1988

Volume

27

Issue

13

Start / End Page

4668 / 4673

Location

United States

Related Subject Headings

  • X-Ray Diffraction
  • Thermodynamics
  • Molecular Conformation
  • Lipid Bilayers
  • Dimyristoylphosphatidylcholine
  • Cholesterol
  • Biochemistry & Molecular Biology
  • 3404 Medicinal and biomolecular chemistry
  • 3205 Medical biochemistry and metabolomics
  • 3101 Biochemistry and cell biology
 

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Needham, D., McIntosh, T. J., & Evans, E. (1988). Thermomechanical and transition properties of dimyristoylphosphatidylcholine/cholesterol bilayers. Biochemistry, 27(13), 4668–4673. https://doi.org/10.1021/bi00413a013
Needham, D., T. J. McIntosh, and E. Evans. “Thermomechanical and transition properties of dimyristoylphosphatidylcholine/cholesterol bilayers.Biochemistry 27, no. 13 (June 28, 1988): 4668–73. https://doi.org/10.1021/bi00413a013.
Needham D, McIntosh TJ, Evans E. Thermomechanical and transition properties of dimyristoylphosphatidylcholine/cholesterol bilayers. Biochemistry. 1988 Jun 28;27(13):4668–73.
Needham, D., et al. “Thermomechanical and transition properties of dimyristoylphosphatidylcholine/cholesterol bilayers.Biochemistry, vol. 27, no. 13, June 1988, pp. 4668–73. Pubmed, doi:10.1021/bi00413a013.
Needham D, McIntosh TJ, Evans E. Thermomechanical and transition properties of dimyristoylphosphatidylcholine/cholesterol bilayers. Biochemistry. 1988 Jun 28;27(13):4668–4673.
Journal cover image

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

June 28, 1988

Volume

27

Issue

13

Start / End Page

4668 / 4673

Location

United States

Related Subject Headings

  • X-Ray Diffraction
  • Thermodynamics
  • Molecular Conformation
  • Lipid Bilayers
  • Dimyristoylphosphatidylcholine
  • Cholesterol
  • Biochemistry & Molecular Biology
  • 3404 Medicinal and biomolecular chemistry
  • 3205 Medical biochemistry and metabolomics
  • 3101 Biochemistry and cell biology