Abstract
Guanidinium is a planar trigonal cation which is similar in size to the gramicidin channel pore. We measured the effect of guanidinium on the conductance properties of the gramicidin channel and theoretically evaluated its interactions with the β-6.3 channel interior using an energy minimization and conformational search approach. Guanidinium current (measured in the absence of other permeable ions) could not be detected directly (g(Guan)/g(K) < 0.004). However, guanidinium induces blocks in gramicidin channel potassium currents. The average block duration gets shorter with increased membrane potential suggesting that guanidinium can penetrate the ion channel. Energy minimization calculations indicate that, by reorienting along the pathway, the guanidinium should be able to penetrate the gramicidin channel. This finding is illustrated by a computer graphics animation of the series of minimum-energy orientations. The low permeability of the channel to guanidinium is tentatively ascribed to an entropic barrier resulting from the restrictions on the ion motion in the channel.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Begenisich, T. B. and M. D. Cahalan. 1980a. ‘Sodium channel permeation in squid axons. I: Reversal potential experiments’. J. Physiol. 307: 217–242.
Begenisich, T. B. and M. D. Cahalan. 1980b. ‘Sodium channel permeation in squid axons. II: Non-independence and current-voltage relations’. J. Physiol. 307: 243–257.
Brooks, B.R., Bruccoleri, R.E., Olafson, B.D., States, D.J., Swaminathan, S., and M. Karplus. 1983. ‘CHARMM: A program for macromolecular energy, minimization, and dynamics calculations’. Journal of Comp. Chem. 4: 187- 217.
Busath, D. and G. Szabo. 1988. ‘Low conductance gramicidin A channels are head-to-head dimers of β-6-helices’. Biophys. J. 53: 689–695.
Colquhoun, D. and F. J. Sigworth. 1983. ‘Fitting and statistical analysis of single-channel records’. In Single-Channel Recording. B Sakmann and E. Neher, eds. Plenum Press, New York, pp 191–263.
Eisenman, G. 1962. ‘Cation selective glass electrodes and their mode of operation’. Biophys. J. 2: 259–323.
Eisenman, G., Krasne, S., and S. Ciani. 1976. ‘Further studies on ion selectivity’. In Ion and Enzyme Electrodes in Medicine and in Biology. M. Kessler, L. Clark, D. Lubbers, J. Silver, and W. Simon, eds. Urban and Schwarzenberg, Munich-Berlin-Vienna, pp 3–22.
Herzig, L., Massa, L.J., Santoro, A., and A.M. Sapse. 1981. ‘Guanidinium Ion Self-Consistent Field Calculations: Fluoro, Amino, and Methyl Single Substituents’. J. Org. Chem. 46: 2330–2333.
Hille, B. 1971. ‘The Permeability of the Sodium Channel to Organic Cations in Myelinated Nerve’. J. Gen. Physiol 58: 599–619.
Hille, B. 1975. ‘Ionic Selectivity of Na and K channels of nerve membranes’. In Membranes - A Series of Advances. Vol 3, Dynamic Properties of Lipid Bilayers and Biological Membranes. G. Eisenman, ed. Marcel Dekker, Inc., New York. 255–323.
Hille, B. 1984. Ionic Channels of Excitable Membranes. Sinauer Associates Inc. Sunderland, MA.
Hladky, S.B. and D.A. Haydon. 1972. ‘Ion transfer across lipid membranes in the presence of gramicidin A. I. Studies of the unit conductance channel’. Biochim. Biophys. Acta. 274: 294–312.
Koeppe, R.E. II and L.B. Weiss. 1981. ‘Resolution of linear gramicidins by preparative reversed-phase high-performance liquid chromatography’. J.Chromatog. 208: 414–418.
McCammon, J. A., Gelin, B. R., and M. Karplus. 1977. ‘Dynamics of folded proteins’. Nature 267: 585–590.
Myers, V. B. and D. A. Haydon. 1972. ‘Ion transfer across lipid membranes in the presence of gramicidin A. II. The ion selectivity’. Biochim. Biophys. Acta 274: 313–322.
Parsegian, A. 1969. ‘Energy of an ion crossing a low dielectric membrane: solutions to four relevant electrostatic problems’. Nature 221: 844–846.
Roux, B. and M. Karplus. 1988. ‘The normal modes of the gramicidin-A dimer channel’. Biophys. J. 53: 297–310.
Urry, D. W., Goodall, M. C, Glickson, J. D., and D. F. Mayers. 1971. ‘The gramicidin A transmembrane channel: Characteristics of head-to-head dimerized pi(L,D) helices’. Proc. Natl Acad. Sci. USA 68: 1907–1911.
Ussing, H. H. 1949. ‘The distinction by means of tracers between active transport and diffusion’. Acta Physiol. Scand. 19: 43–56.
Venkatachalam, C. M. and D. W. Urry. 1983. ‘Theoretical conformational analysis of the gramicidin A transmembrane channel. I. Helix sense and energetics of head-to-head dimerization’. J. Comput. Chem. 4: 461–469.
Venkatachalam, C. M. and D. W. Urry. 1984. ‘Theoretical analysis of gramicidin A transmembrane channel. II. Energetics of helical librational states of the channel’. J. Comput. Chem. 5: 64–71.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1988 Kluwer Academic Publishers
About this paper
Cite this paper
Busath, D., Hemsley, G., Bridal, T., Pear, M., Gaffney, K., Karplus, M. (1988). Guanidinium as a Probe of the Gramicidin Channel Interior. In: Pullman, A., Jortner, J., Pullman, B. (eds) Transport Through Membranes: Carriers, Channels and Pumps. The Jerusalem Symposia on Quantum Chemistry and Biochemistry, vol 21. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-3075-9_13
Download citation
DOI: https://doi.org/10.1007/978-94-009-3075-9_13
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-7882-5
Online ISBN: 978-94-009-3075-9
eBook Packages: Springer Book Archive