Skip to main content
PMC home page
Biophysical Journal logoLink to Biophysical Journal
. 1996 Nov;71(5):2623–2632. doi: 10.1016/S0006-3495(96)79454-7

Measured effects of diacylglycerol on structural and elastic properties of phospholipid membranes.

S Leikin 1, M M Kozlov 1, N L Fuller 1, R P Rand 1
PMCID: PMC1233749  PMID: 8913600

Abstract

Diacylglycerol, a biological membrane second messenger, is a strong perturber of phospholipid planar bilayers. It converts multibilayers to the reverse hexagonal phase (HII), composed of highly curved monolayers. We have used x-ray diffraction and osmotic stress of the HII phase to measure structural dimensions, spontaneous curvature, and bending moduli of dioleoylphosphatidylethanolamine (DOPE) monolayers doped with increasing amounts of dioleoylglycerol (DOG). The diameter of the HII phase cylinders equilibrated in excess water decreases significantly with increasing DOG content. Remarkably, however, all structural dimensions at any specific water/lipid ratio that is less than full hydration are insensitive to DOG. By plotting structural parameters of the HII phase with changing water content in a newly defined coordinate system, we show that the elastic deformation of the lipid monolayers can be described as bending around a pivotal plane of constant area. This dividing surface includes 30% of the lipid volume independent of the DOG content (polar heads and a small fraction of hydrocarbon chains). As the mole fraction of DOG increases to 0.3, the radius of spontaneous curvature defined for the pivotal surface decreases from 29 A to 19 A, and the bending modulus increases from approximately 11 to 14 (+/-0.5) kT. We derive the conversion factors and estimate the spontaneous curvatures and bending moduli for the neutral surface which, unlike the pivotal plane parameters, are intrinsic properties that apply to other deformations and geometries. The spontaneous curvature of the neutral surface differs from that of the pivotal plane by less than 10%, but the difference in the bending moduli is up to 40%. Our estimate shows that the neutral surface bending modulus is approximately 9kT and practically does not depend on the DOG content.

Full text

PDF
2629

Images in this article

2624FIGURE 1
on p.2624
2625FIGURE 2
on p.2625
2626FIGURE 3
on p.2626
2627FIGURE 4
on p.2627
2627FIGURE 5
on p.2627

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Allan D., Michell R. H. Accumulation of 1,2-diacylglycerol in the plasma membrane may lead to echinocyte transformation of erythrocytes. Nature. 1975 Nov 27;258(5533):348–349. doi: 10.1038/258348a0. [DOI] [PubMed] [Google Scholar]
  2. Berridge M. J. Inositol trisphosphate and diacylglycerol as second messengers. Biochem J. 1984 Jun 1;220(2):345–360. doi: 10.1042/bj2200345. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Das S., Rand R. P. Modification by diacylglycerol of the structure and interaction of various phospholipid bilayer membranes. Biochemistry. 1986 May 20;25(10):2882–2889. doi: 10.1021/bi00358a022. [DOI] [PubMed] [Google Scholar]
  4. Dawson R. M., Irvine R. F., Bray J., Quinn P. J. Long-chain unsaturated diacylglycerols cause a perturbation in the structure of phospholipid bilayers rendering them susceptible to phospholipase attack. Biochem Biophys Res Commun. 1984 Dec 14;125(2):836–842. doi: 10.1016/0006-291x(84)90615-6. [DOI] [PubMed] [Google Scholar]
  5. Goldberg E. M., Lester D. S., Borchardt D. B., Zidovetzki R. Effects of diacylglycerols and Ca2+ on structure of phosphatidylcholine/phosphatidylserine bilayers. Biophys J. 1994 Feb;66(2 Pt 1):382–393. doi: 10.1016/s0006-3495(94)80788-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Goldberg E. M., Lester D. S., Borchardt D. B., Zidovetzki R. Effects of diacylglycerols on conformation of phosphatidylcholine headgroups in phosphatidylcholine/phosphatidylserine bilayers. Biophys J. 1995 Sep;69(3):965–973. doi: 10.1016/S0006-3495(95)79970-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Gruner S. M., Parsegian V. A., Rand R. P. Directly measured deformation energy of phospholipid HII hexagonal phases. Faraday Discuss Chem Soc. 1986;(81):29–37. doi: 10.1039/dc9868100029. [DOI] [PubMed] [Google Scholar]
  8. Helfrich W. Elastic properties of lipid bilayers: theory and possible experiments. Z Naturforsch C. 1973 Nov-Dec;28(11):693–703. doi: 10.1515/znc-1973-11-1209. [DOI] [PubMed] [Google Scholar]
  9. LUZZATI V., HUSSON F. The structure of the liquid-crystalline phasis of lipid-water systems. J Cell Biol. 1962 Feb;12:207–219. doi: 10.1083/jcb.12.2.207. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Nieva J. L., Alonso A., Basáez G., Goñi F. M., Gulik A., Vargas R., Luzzati V. Topological properties of two cubic phases of a phospholipid:cholesterol:diacylglycerol aqueous system and their possible implications in the phospholipase C-induced liposome fusion. FEBS Lett. 1995 Jul 10;368(1):143–147. doi: 10.1016/0014-5793(95)00631-i. [DOI] [PubMed] [Google Scholar]
  11. Nishizuka Y. The role of protein kinase C in cell surface signal transduction and tumour promotion. Nature. 1984 Apr 19;308(5961):693–698. doi: 10.1038/308693a0. [DOI] [PubMed] [Google Scholar]
  12. Rand R. P., Fuller N. L., Gruner S. M., Parsegian V. A. Membrane curvature, lipid segregation, and structural transitions for phospholipids under dual-solvent stress. Biochemistry. 1990 Jan 9;29(1):76–87. doi: 10.1021/bi00453a010. [DOI] [PubMed] [Google Scholar]
  13. Rand R. P., Fuller N. L. Structural dimensions and their changes in a reentrant hexagonal-lamellar transition of phospholipids. Biophys J. 1994 Jun;66(6):2127–2138. doi: 10.1016/S0006-3495(94)81008-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Siegel D. P. Energetics of intermediates in membrane fusion: comparison of stalk and inverted micellar intermediate mechanisms. Biophys J. 1993 Nov;65(5):2124–2140. doi: 10.1016/S0006-3495(93)81256-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Turner D. C., Gruner S. M. X-ray diffraction reconstruction of the inverted hexagonal (HII) phase in lipid-water systems. Biochemistry. 1992 Feb 11;31(5):1340–1355. doi: 10.1021/bi00120a009. [DOI] [PubMed] [Google Scholar]
  16. Wakelam M. J. Inositol phospholipid metabolism and myoblast fusion. Biochem J. 1983 Jul 15;214(1):77–82. doi: 10.1042/bj2140077. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Whitaker M., Aitchison M. Calcium-dependent polyphosphoinositide hydrolysis is associated with exocytosis in vitro. FEBS Lett. 1985 Mar 11;182(1):119–124. doi: 10.1016/0014-5793(85)81167-4. [DOI] [PubMed] [Google Scholar]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society

RESOURCES