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. 1994 Dec;67(6):2265–2271. doi: 10.1016/S0006-3495(94)80711-8

Hofmeister effect in ion transport: reversible binding of halide anions to the roflamycoin channel.

P A Grigorjev 1, S M Bezrukov 1
PMCID: PMC1225610  PMID: 7535110

Abstract

We have studied the anion-dependent gating of roflamycoin ion channels using spectral analysis of noise in currents through multichannel planar lipid bilayers. We have found that in addition to low frequency current fluctuations that may be attributed to channel switching between open and closed conformations, roflamycoin channels exhibit a pronounced higher frequency noise indicating that the open channel conductance has substates with short lifetimes. This noise is well described by a Lorentzian spectrum component with a characteristic cutoff frequency that depends on the type of halide anions according to their position in the Hofmeister series. It is suggested that transitions between the substates correspond to a reversible ionization of the channel by a penetrating anion that binds to the channel structure, more chaotropic anions being bound for longer times. Within a framework of a two-substate model, the duration of the substate with reduced electrostatic barrier for cation current varies exponentially with anion electron polarizability. This explains two features of the roflamycoin channel reported earlier: the increase in apparent single-channel conductance along the series F- < Cl- < Br- < I- and the reverse of channel selectivity from anionic for KF to cationic for KI.

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Selected References

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

  1. Bezrukov SM, Kasianowicz JJ. Current noise reveals protonation kinetics and number of ionizable sites in an open protein ion channel. Phys Rev Lett. 1993 Apr 12;70(15):2352–2355. doi: 10.1103/PhysRevLett.70.2352. [DOI] [PubMed] [Google Scholar]
  2. Collins K. D., Washabaugh M. W. The Hofmeister effect and the behaviour of water at interfaces. Q Rev Biophys. 1985 Nov;18(4):323–422. doi: 10.1017/s0033583500005369. [DOI] [PubMed] [Google Scholar]
  3. Ermishkin L. N., Kasumov K. M., Potseluyev V. M. Properties of amphotericin B channels in a lipid bilayer. Biochim Biophys Acta. 1977 Nov 1;470(3):357–367. doi: 10.1016/0005-2736(77)90127-4. [DOI] [PubMed] [Google Scholar]
  4. Finkelstein A., Holz R. Aqueous pores created in thin lipid membranes by the polyene antibiotics nystatin and amphotericin B. Membranes. 1973;2:377–408. [PubMed] [Google Scholar]
  5. Grigorjev P., Schlegel R., Thrum H., Ermishkin L. Roflamycoin--a new channel-forming antibiotic. Biochim Biophys Acta. 1985 Dec 5;821(2):297–304. doi: 10.1016/0005-2736(85)90099-9. [DOI] [PubMed] [Google Scholar]
  6. Heinemann S. H., Sigworth F. J. Open channel noise. V. Fluctuating barriers to ion entry in gramicidin A channels. Biophys J. 1990 Mar;57(3):499–514. doi: 10.1016/S0006-3495(90)82566-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Hess P., Prod'Hom B., Pietrobon D. Mechanisms of interaction of permeant ions and protons with dihydropyridine-sensitive calcium channels. Ann N Y Acad Sci. 1989;560:80–93. doi: 10.1111/j.1749-6632.1989.tb24082.x. [DOI] [PubMed] [Google Scholar]
  8. Prod'hom B., Pietrobon D., Hess P. Direct measurement of proton transfer rates to a group controlling the dihydropyridine-sensitive Ca2+ channel. Nature. 1987 Sep 17;329(6136):243–246. doi: 10.1038/329243a0. [DOI] [PubMed] [Google Scholar]
  9. Schlegel R., Thrum H. A new polyene antibiotic, flavomycoin. Structural investigations. II. J Antibiot (Tokyo) 1971 Jun;24(6):368–374. doi: 10.7164/antibiotics.24.368. [DOI] [PubMed] [Google Scholar]
  10. Verveen A. A., DeFelice L. J. Membrane noise. Prog Biophys Mol Biol. 1974;28:189–265. doi: 10.1016/0079-6107(74)90019-4. [DOI] [PubMed] [Google Scholar]
  11. Washabaugh M. W., Collins K. D. The systematic characterization by aqueous column chromatography of solutes which affect protein stability. J Biol Chem. 1986 Sep 25;261(27):12477–12485. [PubMed] [Google Scholar]
  12. de Kruijff B., Demel R. A. Polyene antibiotic-sterol interactions in membranes of Acholeplasma laidlawii cells and lecithin liposomes. 3. Molecular structure of the polyene antibiotic-cholesterol complexes. Biochim Biophys Acta. 1974 Feb 26;339(1):57–70. doi: 10.1016/0005-2736(74)90332-0. [DOI] [PubMed] [Google Scholar]

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