Journal of Chemical Physics
Feedback | Help | Exit
The Journal of Chemical Physics
Search:
   
 
 
 
Previous Article
Phase equilibria in DOPC/DPPC: Conversion from gel to subgel in two component mixtures
Biological membranes contain a mixture of phospholipids with varying degrees of hydrocarbon chain unsaturation. Mixtures of long chain saturated and unsaturated lipids with cholesterol have attracted ...
Next Article
Erratum: “Interaction between silver nanowires and CO on a stepped platinum surface” [J. Chem. Phys. 131, 064702 (2009)]

Density imbalances and free energy of lipid transfer in supported lipid bilayers

J. Chem. Phys. 131, 175104 (2009); doi:10.1063/1.3262315

Published 6 November 2009

You are not logged in to this journal. Log in

Chenyue Xing and Roland Faller
Department of Chemical Engineering and Materials Science, UC Davis, Davis, California 95616, USA
Supported lipid bilayers are an abundant research platform for understanding the behavior of real cell membranes as they allow for additional mechanical stability and at the same time have a fundamental structure approximating cell membranes. However, in computer simulations these systems have been studied only rarely up to now. An important property, which cannot be easily determined by molecular dynamics or experiments, is the unsymmetrical density profiles of bilayer leaflets (density imbalance) inflicted on the membrane by the support. This imbalance in the leaflets composition has consequences for membrane structure and phase behavior, and therefore we need to understand it in detail. The free energy can be used to determine the equilibrium structure of a given system. We employ an umbrella sampling approach to obtain the free energy of a lipid crossing the membrane (i.e., lipid flip-flop) as a function of bilayer composition and hence the equilibrium composition of the supported bilayers. In this paper, we use a variant of the coarse-grained Martini model. The results of the free energy calculation lead to a 5% higher density in the proximal leaflet. Recent data obtained by large scale modeling using a water free model suggested that the proximal leaflet had 3.2% more lipids than the distal leaflet [Hoopes et al., J. Chem. Phys. 129, 175102 (2008)]. Our findings are in line with these results. We compare results of the free energy of transport obtained by pulling the lipid across the membrane in different ways. There are small quantitative differences, but the overall picture is consistent. We additionally characterize the intermediate states, which determine the barrier height and therefore the rate of translocation. Calculations on unsupported bilayers are used to validate the approach and to determine the barrier to flip-flop in a free membrane. ©2009 American Institute of Physics
History: Received 11 June 2009; accepted 19 October 2009; published 6 November 2009
Permalink: http://link.aip.org/link/?JCPSA6/131/175104/1
BUY THIS ARTICLE   (US$24)
Download HTML Download Sectioned HTML Download PDF (990 kB) View Cart

KEYWORDS and PACS

Keywords
PACS
  • 87.16.dp
    Transport in biomembranes, bilayers and vesicles
  • 02.50.-r
    Probability theory, stochastic processes, and statistics
  • 87.16.dt
    Structure of biomembranes, bilayers and vesicles
  • 87.14.Cc
    Lipids (biomolecules)
  • YEAR: 2009

PUBLICATION DATA

ISSN:
0021-9606 (print)   1089-7690 (online)
Publisher:
AIP is a member of CrossRef AIP

REFERENCES (27)
View in Separate Window/Tab
For access to fully linked references, you need to log in. For access to fully linked references, you need to Log in.
  1. E. Sackmann, Science 271, 43 (1996).
  2. J. T. Groves, N. Ulman, and S. G. Boxer, Science 275, 651 (1997)
  3. K. C. Weng, J. J. R. Stalgren, S. H. Risbud, and C. W. Frank, J. Non-Cryst. Solids 350, 46 (2004).
  4. J. T. Groves and M. L. Dustin, J. Immunol. Methods 278, 19 (2003)
  5. B. A. Cornell, V. L. B. BraachMaksvytis, L. G. King, P. D. J. Osman, B. Raguse, L. Wieczorek, and R. J. Pace, Nature (London) 387, 580 (1997).
  6. D. R. Heine, A. R. Rammohan, and J. Balakrishnan, Mol. Simul. 33, 391 (2007)
  7. M. Roark and S. E. Feller, Langmuir 24, 12469 (2008).
  8. C. Xing and R. Faller, J. Phys. Chem. B 112, 7086 (2008).
  9. M. I. Hoopes, M. Deserno, M. L. Longo, and R. Faller, J. Chem. Phys. 129, 175102 (2008).
  10. C. Xing, O. H. S. Ollila, I. Vattulainen, and R. Faller, Soft Matter 5, 3258 (2009).
  11. M. I. Hoopes, C. Xing, and R. Faller, in Handbook in Modern Biophysics 2: Biomembrane Frontiers: Nanostructures, Models, and the Design of Life, edited by R. Faller, T. Jue, M. L. Longo, and S. H. Risbud (Springer-Humana, Totowa, NJ, 2009), Vol. 2, p. 101.
  12. O. Berger, O. Edholm, and F. Jahnig, Biophys. J. 72, 2002 (1997)
    13. S. E. Feller, D. Yin, R. W. Pastor, and A. D. MacKerell, Jr., ibid. 73, 2269 (1997)
    C. J. Hogberg and A. P. Lyubartsev, J. Phys. Chem. B 110, 14326 (2006)
    S. J. Marrink, E. Lindahl, O. Edholm, and A. E. Mark, J. Am. Chem. Soc. 123, 8638 (2001).
  13. E. Falck, M. Patra, M. Karttunen, M. T. Hyvonen, and I. Vattulainen, Biophys. J. 87, 1076 (2004)
    14. R. Goetz and R. Lipowsky, J. Chem. Phys. 108, 7397 (1998)
    O. G. Mouritsen, Chem. Phys. Lipids 57, 179 (1991)
    P. Niemela, M. T. Hyvonen, and I. Vattulainen, Biophys. J. 87, 2976 (2004)
    S. Leekumjorn and A. K. Sum, ibid. 90, 3951 (2006).
  14. R. Faller and S. -J. Marrink, Langmuir 20, 7686 (2004).
  15. M. Müller, K. Katsov, and M. Schick, Phys. Rep. 434, 113 (2006)
    16. S. J. Marrink, J. Risselada, and A. E. Mark, Chem. Phys. Lipids 135, 223 (2005).
  16. C. Kandt, W. L. Ash, and D. P. Tieleman, Methods 41, 475 (2007).
  17. A. N. Dickey and R. Faller, J. Polym. Sci., Part B: Polym. Phys. 43, 1025 (2005)
    18. E. Jakobsson, Trends Biochem. Sci. 22, 339 (1997)
    C. Hofsas, E. Lindahl, and O. Edholm, Biophys. J. 84, 2192 (2003)
    M. Patra, Eur. Biophys. J. 35, 79 (2005).
  18. A. K. Sum, R. Faller, and J. J. de Pablo, Biophys. J. 85, 2830 (2003).
  19. H. M. McConnell and R. D. Kornberg, Biochemistry 10, 1111 (1971).
  20. C. F. Lopez, P. B. Moore, J. C. Shelley, M. Y. Shelley, and M. L. Klein, Comput. Phys. Commun. 147, 1 (2002).
  21. S. J. Marrink, H. J. Risselada, S. Yefimov, D. P. Tieleman, and A. H. de Vries, J. Phys. Chem. B 111, 7812 (2007).
  22. A. N. Dickey and R. Faller, Biophys. J. 92, 2366 (2007).
  23. D. P. Tieleman and S. J. Marrink, J. Am. Chem. Soc. 128, 12462 (2006).
  24. G. M. Torrie and J. P. Valleau, J. Comput. Phys. 23, 187 (1977).
  25. S. J. Marrink, A. H. de Vries, and A. E. Mark, J. Phys. Chem. B 108, 750 (2004).
  26. B. Silver, Physical Chemistry of Membranes: An Introduction to the Structure and Dynamics of Biological Membranes (Kluwer Academic, Dordrecht, 1985).
  27. S. Bennun, A. N. Dickey, C. Xing, and R. Faller, Fluid Phase Equilib. 261, 18 (2007).
  28. E. Lindahl, B. Hess, and D. van der Spoel, J. Mol. Model. 7, 306 (2001)
    29. H. J. C. Berendsen, D. van der Spoel, and R. van Drunen, Comput. Phys. Commun. 91, 43 (1995).
  29. S. Kumar, J. M. Rosenberg, D. Bouzida, R. H. Swendsen, and P. A. Kollman, J. Comput. Chem. 16, 1339 (1995)
    30. B. Roux, Comput. Phys. Commun. 91, 275 (1995).
  30. W. Humphrey, A. Dalke, and K. Schulten, J. Mol. Graphics 14, 33 (1996).

CITING ARTICLES
For access to citing articles, you need to log in.
For access to citing articles, you need to Log in.


Copyright © American Institute of Physics