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Long- and short-range interactions between phospholipid/ganglioside GM1 bilayers.

Publication ,  Journal Article
McIntosh, TJ; Simon, SA
Published in: Biochemistry
August 30, 1994

The structure and interactive properties of liquid-crystalline egg phosphatidylcholine (EPC) bilayers containing the ganglioside GM1 and its uncharged analogue, asialoGM1 (AGM1), have been obtained by X-ray diffraction analysis of osmotically stressed liposomes. Both electron density profiles and reciprocal space modeling indicate that (1) the incorporation of up to 30 mol % GM1 into EPC bilayers has little effect on bilayer organization and (2) the oligosaccharide portion of the GM1 molecule extends at least 12 A beyond the EPC head group into the fluid space, implying that the GM1 head group is nearly fully extended from the bilayer surface. Pressure-distance relations for EPC:GM1 bilayers in 100 mM ionic strength buffer show that, for large bilayer separations, the interbilayer repulsive pressure decays exponentially with a decay length and magnitude expected for electrostatic repulsion arising from the charged GM1. However, at interbilayer separations of < or = 30 A for 7:3 and 8:2 EPC:GM1 and < or = 22 A for 9:1 EPC:GM1, the pressure-distance curves have distinct upward breaks, with the sharpness of this break depending strongly on the amount of GM1 in the bilayer. For 7:3 EPC:GM1 bilayers, the break is quite sharp so that the distance between bilayers does not decrease below 28 A with further increases in applied pressure. For EPC:GM1 8:2 and 9:1 bilayers, the upward break becomes softer with decreasing GM1 concentration. For uncharged EPC:AGM1 bilayers, the repulsive pressure extends only to an equilibrium fluid separation of about 36 A, but has a similar behavior to the pressure-distance data for EPC:GM1 for separations below 20 A. We argue that the nonelectrostatic repulsive pressures arise primarily from the steric interactions between the hydrated oligosaccharide head groups that protrude from the bilayer surface.

Duke Scholars

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

August 30, 1994

Volume

33

Issue

34

Start / End Page

10477 / 10486

Location

United States

Related Subject Headings

  • X-Ray Diffraction
  • Phosphatidylcholines
  • Models, Molecular
  • Liposomes
  • Lipid Bilayers
  • In Vitro Techniques
  • G(M1) Ganglioside
  • Electrochemistry
  • Cattle
  • Biochemistry & Molecular Biology
 

Citation

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McIntosh, T. J., & Simon, S. A. (1994). Long- and short-range interactions between phospholipid/ganglioside GM1 bilayers. Biochemistry, 33(34), 10477–10486. https://doi.org/10.1021/bi00200a032
McIntosh, T. J., and S. A. Simon. “Long- and short-range interactions between phospholipid/ganglioside GM1 bilayers.Biochemistry 33, no. 34 (August 30, 1994): 10477–86. https://doi.org/10.1021/bi00200a032.
McIntosh TJ, Simon SA. Long- and short-range interactions between phospholipid/ganglioside GM1 bilayers. Biochemistry. 1994 Aug 30;33(34):10477–86.
McIntosh, T. J., and S. A. Simon. “Long- and short-range interactions between phospholipid/ganglioside GM1 bilayers.Biochemistry, vol. 33, no. 34, Aug. 1994, pp. 10477–86. Pubmed, doi:10.1021/bi00200a032.
McIntosh TJ, Simon SA. Long- and short-range interactions between phospholipid/ganglioside GM1 bilayers. Biochemistry. 1994 Aug 30;33(34):10477–10486.
Journal cover image

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

August 30, 1994

Volume

33

Issue

34

Start / End Page

10477 / 10486

Location

United States

Related Subject Headings

  • X-Ray Diffraction
  • Phosphatidylcholines
  • Models, Molecular
  • Liposomes
  • Lipid Bilayers
  • In Vitro Techniques
  • G(M1) Ganglioside
  • Electrochemistry
  • Cattle
  • Biochemistry & Molecular Biology