Abstract
The energetics of phospholipid aggregation depend on the apparent water-accessible apolar surface area (ASAap), ordering effects of the chains, and headgroup interactions. We quantify the enthalpy and entropy of these interactions separately. For that purpose, the thermodynamics of micelle formation of lysophosphatidylcholines (LPCs, chains C10, C12, C14, and C16) and diacylphosphatidylcholines (DAPCs, chains C5, C6) and C7) are studied using isothermal titration calorimetry. The critical micelle concentration (CMC) values are 90, 15, and 1.9 mM (C5-C7-DAPC) and 6.8, 0.71, 0.045, and 0.005 mM (LPCs). The group contributions per methylene of DeltaDeltaG(0) = -3.1 kJ/mol and DeltaDeltaC(P) = -57 J/(mol. K) for LPCs agree with literature data on hydrocarbons and amphiphiles. An apparent deviation of DAPCs (-2.5 kJ/mol, 45 J/(mol. K)) is due to an intramolecular interaction between the two chains, burying 20% of the surface. The chain/chain interaction enthalpies in a micelle core are by approximately -2 kJ/(mol) per methylene group more favorable than in bulk hydrocarbons. We conclude that the impact of the chain conformation and packing on the interaction enthalpy is very pronounced. It serves to explain a variety of effects reported on membrane binding. Interactions within the water-accessible region show considerable DeltaH, but almost no DeltaG(0). The heat capacity changes suggest about three methylene groups (ASAap approximately 100 A2) per LPC remain exposed to water in a micelle (DAPC: 2 CH2/70 A2).
Full Text
The Full Text of this article is available as a PDF (112.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Baker B. M., Murphy K. P. Prediction of binding energetics from structure using empirical parameterization. Methods Enzymol. 1998;295:294–315. doi: 10.1016/s0076-6879(98)95045-5. [DOI] [PubMed] [Google Scholar]
- Chernomordik L. Non-bilayer lipids and biological fusion intermediates. Chem Phys Lipids. 1996 Jul 15;81(2):203–213. doi: 10.1016/0009-3084(96)02583-2. [DOI] [PubMed] [Google Scholar]
- De Young L. R., Dill K. A. Solute partitioning into lipid bilayer membranes. Biochemistry. 1988 Jul 12;27(14):5281–5289. doi: 10.1021/bi00414a050. [DOI] [PubMed] [Google Scholar]
- Epand R. M., Epand R. F. Calorimetric detection of curvature strain in phospholipid bilayers. Biophys J. 1994 May;66(5):1450–1456. doi: 10.1016/S0006-3495(94)80935-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gill S. J., Wadsö I. An equation of state describing hydrophobic interactions. Proc Natl Acad Sci U S A. 1976 Sep;73(9):2955–2958. doi: 10.1073/pnas.73.9.2955. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heerklotz H., Seelig J. Correlation of membrane/water partition coefficients of detergents with the critical micelle concentration. Biophys J. 2000 May;78(5):2435–2440. doi: 10.1016/S0006-3495(00)76787-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heerklotz H., Seelig J. Titration calorimetry of surfactant-membrane partitioning and membrane solubilization. Biochim Biophys Acta. 2000 Nov 23;1508(1-2):69–85. doi: 10.1016/s0304-4157(00)00009-5. [DOI] [PubMed] [Google Scholar]
- Israelachvili J., Wennerström H. Role of hydration and water structure in biological and colloidal interactions. Nature. 1996 Jan 18;379(6562):219–225. doi: 10.1038/379219a0. [DOI] [PubMed] [Google Scholar]
- Kessi J., Poirée J. C., Wehrli E., Bachofen R., Semenza G., Hauser H. Short-chain phosphatidylcholines as superior detergents in solubilizing membrane proteins and preserving biological activity. Biochemistry. 1994 Sep 6;33(35):10825–10836. doi: 10.1021/bi00201a033. [DOI] [PubMed] [Google Scholar]
- Killian J. A. Hydrophobic mismatch between proteins and lipids in membranes. Biochim Biophys Acta. 1998 Nov 10;1376(3):401–415. doi: 10.1016/s0304-4157(98)00017-3. [DOI] [PubMed] [Google Scholar]
- Kluge S., Gawrisch K., Nuhn P. Loss of infectivity of red clover mottle virus by lysolecithin. Acta Virol. 1987 Mar;31(2):185–188. [PubMed] [Google Scholar]
- Koynova R., Caffrey M. Phases and phase transitions of the glycoglycerolipids. Chem Phys Lipids. 1994 Mar 1;69(3):181–207. doi: 10.1016/0009-3084(94)90001-9. [DOI] [PubMed] [Google Scholar]
- Ludtke S., He K., Huang H. Membrane thinning caused by magainin 2. Biochemistry. 1995 Dec 26;34(51):16764–16769. doi: 10.1021/bi00051a026. [DOI] [PubMed] [Google Scholar]
- Murphy K. P., Gill S. J. Solid model compounds and the thermodynamics of protein unfolding. J Mol Biol. 1991 Dec 5;222(3):699–709. doi: 10.1016/0022-2836(91)90506-2. [DOI] [PubMed] [Google Scholar]
- Murphy K. P., Privalov P. L., Gill S. J. Common features of protein unfolding and dissolution of hydrophobic compounds. Science. 1990 Feb 2;247(4942):559–561. doi: 10.1126/science.2300815. [DOI] [PubMed] [Google Scholar]
- Nagle J. F. Lipid bilayer phase transition: density measurements and theory. Proc Natl Acad Sci U S A. 1973 Dec;70(12):3443–3444. doi: 10.1073/pnas.70.12.3443. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nagle J. F., Tristram-Nagle S. Structure of lipid bilayers. Biochim Biophys Acta. 2000 Nov 10;1469(3):159–195. doi: 10.1016/s0304-4157(00)00016-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nagle J. F., Zhang R., Tristram-Nagle S., Sun W., Petrache H. I., Suter R. M. X-ray structure determination of fully hydrated L alpha phase dipalmitoylphosphatidylcholine bilayers. Biophys J. 1996 Mar;70(3):1419–1431. doi: 10.1016/S0006-3495(96)79701-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nebel S., Ganz P., Seelig J. Heat changes in lipid membranes under sudden osmotic stress. Biochemistry. 1997 Mar 11;36(10):2853–2859. doi: 10.1021/bi961839n. [DOI] [PubMed] [Google Scholar]
- Sanders C. R., 2nd, Landis G. C. Reconstitution of membrane proteins into lipid-rich bilayered mixed micelles for NMR studies. Biochemistry. 1995 Mar 28;34(12):4030–4040. doi: 10.1021/bi00012a022. [DOI] [PubMed] [Google Scholar]
- Seelig J., Ganz P. Nonclassical hydrophobic effect in membrane binding equilibria. Biochemistry. 1991 Sep 24;30(38):9354–9359. doi: 10.1021/bi00102a031. [DOI] [PubMed] [Google Scholar]
- Seelig J., Seelig A. Lipid conformation in model membranes and biological membranes. Q Rev Biophys. 1980 Feb;13(1):19–61. doi: 10.1017/s0033583500000305. [DOI] [PubMed] [Google Scholar]
- Seelig J. Titration calorimetry of lipid-peptide interactions. Biochim Biophys Acta. 1997 Mar 14;1331(1):103–116. doi: 10.1016/s0304-4157(97)00002-6. [DOI] [PubMed] [Google Scholar]
- Spolar R. S., Livingstone J. R., Record M. T., Jr Use of liquid hydrocarbon and amide transfer data to estimate contributions to thermodynamic functions of protein folding from the removal of nonpolar and polar surface from water. Biochemistry. 1992 Apr 28;31(16):3947–3955. doi: 10.1021/bi00131a009. [DOI] [PubMed] [Google Scholar]
- Tausk R. J., Karmiggelt J., Oudshoorn C., Overbeek J. T. Physical chemical studies of short-chain lecithin homologues. I. Influence of the chain length of the fatty acid ester and of electrolytes on the critical micelle concentration. Biophys Chem. 1974 Feb;1(3):175–183. doi: 10.1016/0301-4622(74)80004-9. [DOI] [PubMed] [Google Scholar]
- Wiener M. C., White S. H. Structure of a fluid dioleoylphosphatidylcholine bilayer determined by joint refinement of x-ray and neutron diffraction data. III. Complete structure. Biophys J. 1992 Feb;61(2):434–447. doi: 10.1016/S0006-3495(92)81849-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wieprecht T, Apostolov O, Seelig J. Binding of the antibacterial peptide magainin 2 amide to small and large unilamellar vesicles. Biophys Chem. 2000 Jul 15;85(2-3):187–198. doi: 10.1016/s0301-4622(00)00120-4. [DOI] [PubMed] [Google Scholar]
- Yuan Y., Schoenwaelder S. M., Salem H. H., Jackson S. P. The bioactive phospholipid, lysophosphatidylcholine, induces cellular effects via G-protein-dependent activation of adenylyl cyclase. J Biol Chem. 1996 Oct 25;271(43):27090–27098. doi: 10.1074/jbc.271.43.27090. [DOI] [PubMed] [Google Scholar]