Springer Nature is making Coronavirus research free. View research | View latest news | Sign up for updates

Asymmetry of the gramicidin channel in bilayers of asymmetric lipid composition: II. Voltage dependence of dimerization

  • 32 Accesses

  • 3 Citations


The asymmetric current-voltage relationship of gramicidin-doped asymmetric bilayers made by the Montal-Mueller technique was investigated in current relaxation experiments. It was shown that, in addition to the contribution of the asymmetric single channel conductance to the asymmetry of the steady-state current-voltage relationship, there is an asymmetric voltage dependence of the step which leads to the formation of the conducting channel. This asymmetric voltage dependence could be simulated in a model assuming a membrane-internal electrical potential drop or an equivalent potential, called asymmetry potential, which could be compensated by externally applying an offset potential. Significant asymmetry potentials were found in asymmetric bilayers made of charged lipids or only of neutral lipids. The asymmetry potential, was dependent on the salt composition in the aqueous phase.

The factors responsible for the asymmetry potential do not appear to be of electrostatic origin. Several lines of evidence suggest that the dimerization step which leads to the conducting ion channel may be a complex series of reactions which are influenced by one or more membrane structural properties not yet characterized, in addition to the effects of the externally applied electric field.

This is a preview of subscription content, log in to check access.


  1. Alvarez, O., Latorre, R. 1978. Voltage-dependent capacitance in lipid bilayers made from monolayers.Biophys. J. 21:1

  2. Anderson, O.S., Finkelstein, A., Katz, I., Cass, A. 1976. The effect of phloretin on the permeability of thin lipid membranes.J. Gen. Physiol. 67:749

  3. Apell, H.J., Bamberg, E., Alpes, H., Läuger, P. 1977. Formation of ion channels by a negatively charged anlaog of gramicidin A.J. Membrane Biol. 31:171

  4. Bamberg, E., Apell, H.-J., Alpes, H. 1977. Structure of the gramicidin A channel: Discrimination between theπ L,D and the β helix by electrical measurements with lipid bilayer membranes.Proc. Nat. Acad. Sci. USA 74:2404

  5. Bamberg, E., Benz, R. 1976. Voltage-induced thickness changes of lipid bilayer membranes and the effect of an electrical field on gramicidin channel formation.Biochim. Biophys. Acta 426:570

  6. Bamberg, E., Läuger, P. 1973. Channel formation kinetics of gramicidin A in lipid bilayer membranes.J. Membrane Biol. 11:177

  7. Benz, R., Fröhlich, O., Läuger, P., Montal, M. 1975. Electrical capacity of black lipid films and of lipid bilayers made from monolayers.Biochim. Biophys. Acta 394:323

  8. Bradley, R.J., Urry, D.W., Okamoto, K., Rapaka, R. 1978. Channel structures of gramicidin. Characterization of succinyl derivatives.Science 200:435

  9. Fröhlich, O. 1979. Asymmetry of the gramicidin channel in bilayers of asymmetric lipid distribution. I. Single channel conductance.J. Membrane Biol. 48:365

  10. Hladky, S.B., Haydon, D.A. 1973. Membrane conductance and surface potential.Biochim. Biophys. Acta 318:464

  11. Hladky, S.B., Urban, B.W., Haydon, D.A. 1978. Ion movements in pores formed by gramicidin A.In: Membrane Transport Processes, Vol. 3. C. Stevens, R. Tsien, W. Chandler, editors. Raven Press, New York

  12. Kolb, H.-A., Bamberg, E. 1977. Influence of membrane thickness and ion concentration on the properties of the gramicidin A channel. Autocorrelation, spectral power density, relaxation and single channel studies.Biochim. Biophys. Acta 464:127

  13. Latorre, R., Hall, J.E. 1976. Dipole potential measurements in asymmetric membranes.Nature (London) 264:361

  14. Levitt, D.G. 1978. Electrostatic calculations for an ion channel. II. Kinetic behavior of the gramicidin A channel.Biophys. J. 22:221

  15. Montal, M., Mueller, P. 1972. Formation of bimolecular membranes, from monolayers and a study of their electrical properties.Proc. Nat. Acad. Sci. USA 69:3561

  16. Neher, E., Eibl, H. 1977. The influence of phospholipid polar groups on gramicidin channels.Biochim., Biophys. Acta 464:37

  17. Paltauf, F., Hauser, H., Phillips, M.C. 1971. Monolayer characteristics of some 1,2-diacyl, 1-alkyl-2-acyl and 1,2-dialkyl phosphlipids at the air-water interface.Biochim. Biophys. Acta 249:539

  18. Requena, J., Haydon, D.A., Hladky, S.B. 1975. Lenses and the compression of black lipid membranes by an electric field.Biophys. J. 15:77

  19. Szabo, G. 1975. Dual mechanism for the action of cholesterol on membrane permeability.Nature (London) 252:47

  20. Tosteson, D.C., Andreoli, T.E., Tieffenberg, M., Cook, P. 1968. The effects of macrocyclic compounds on cation transport in sheep red cells and thin and thick lipid membranes.J. Gen. Physiol. 51:373s

  21. Urry, D.W. 1971. The gramicidin A transmembrane channel: A proposedπ L,D helix.Proc. Nat. Acad. Sci. USA 68:672

  22. Urry, D.W. 1972. A molecular theory of ion-conducting channels: A field-dependent transition between conducting and nonconducting conformations.Proc. Nat. Acad. Sci. USA 69:1610

  23. Urry, D.W., Glickson, J.D., Mayers, D.F., Haider, J. 1972. Spectroscopic studies on the conformation of gramicidin A. Evidence for a new helical conformation.Biochemistry 11:487

  24. Urry, D.W., Goodall, M.C., Glickson, J.D., Mayers, D.F. 1971. The gramicidin A transmembrane channel: Characteristics of head-to-head dimerizedπ L,D, helices.Proc. Nat. Acad. Sci. USA 68:1901

  25. Urry, D.W., Long, M.M., Jacobs, M., Harris, R.D. 1975. Conformation and molecular mechanisms of carriers and channels.Ann. N.Y. Acad. Sci. 264:203

  26. Veatch, W.R., Blout, E.R. 1974. The aggregation of gramicidin A in solution.Biochemistry 13:5257

  27. Veatch, W.R., Fossel, R.T., Blout, E.R. 1974. The conformation of gramicidin A.Biochemistry 13:5249

  28. Veatch, W.R., Mathies, R., Eisenberg, M., Stryer, L. 1975. Simultaneous fluorescence and conductance studies of planar bilayer membranes containing a highly active and fluorescent analog of gramicidin A.J. Mol. Biol. 99:75

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Fröhlich, O. Asymmetry of the gramicidin channel in bilayers of asymmetric lipid composition: II. Voltage dependence of dimerization. J. Membrain Biol. 48, 385–401 (1979).

Download citation


  • Neutral Lipid
  • Voltage Dependence
  • Gramicidin
  • Single Channel Conductance
  • Relaxation Experiment