Mechanism for proton conduction of the M2 ion channel of influenza A virus

Jorgen A. Mould, Hui Chun Li, Christine S. Dudlak, James D. Lear, Andrew Pekosz, Robert A. Lamb, Lawrence H. Pinto

Research output: Contribution to journalArticle

Abstract

The M2 integral membrane protein of influenza A virus forms a proton- selective ion channel. We investigated the mechanism for proton transport of the M2 protein in Xenopus oocytes using a two-electrode voltage clamp and in CV-1 cells using the whole cell patch clamp technique. Membrane currents were recorded while manipulating the external solution to alter either the total or free proton concentration or the solvent itself. Membrane conductance decreased by ~50% when D2O replaced H2O as the solvent. From this, we conclude that hydrogen ions do not pass through M2 as hydronium ions, but instead must interact with titratable groups that line the pore of the channel. M2 currents measured in solutions of low buffer concentration (2 current amplitude in 15 mM buffer decreased when pH-pK(a) was increased by changing the buffer pK(a). Collectively, these results demonstrate that M2 currents can be limited by external buffer capacity. The data presented in this study were also used to estimate the maximum single channel current of the M2 ion channel, which was calculated to be on the order of 1-10 fA.

Original languageEnglish (US)
Pages (from-to)8592-8599
Number of pages8
JournalJournal of Biological Chemistry
Volume275
Issue number12
DOIs
StatePublished - Mar 24 2000
Externally publishedYes

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Influenza A virus
Ion Channels
Viruses
Protons
Buffers
Clamping devices
Membranes
Patch-Clamp Techniques
Xenopus
Oocytes
Carrier Proteins
Electrodes
Membrane Proteins
Electric potential
Proteins

ASJC Scopus subject areas

  • Biochemistry

Cite this

Mould, J. A., Li, H. C., Dudlak, C. S., Lear, J. D., Pekosz, A., Lamb, R. A., & Pinto, L. H. (2000). Mechanism for proton conduction of the M2 ion channel of influenza A virus. Journal of Biological Chemistry, 275(12), 8592-8599. https://doi.org/10.1074/jbc.275.12.8592

Mechanism for proton conduction of the M2 ion channel of influenza A virus. / Mould, Jorgen A.; Li, Hui Chun; Dudlak, Christine S.; Lear, James D.; Pekosz, Andrew; Lamb, Robert A.; Pinto, Lawrence H.

In: Journal of Biological Chemistry, Vol. 275, No. 12, 24.03.2000, p. 8592-8599.

Research output: Contribution to journalArticle

Mould, JA, Li, HC, Dudlak, CS, Lear, JD, Pekosz, A, Lamb, RA & Pinto, LH 2000, 'Mechanism for proton conduction of the M2 ion channel of influenza A virus', Journal of Biological Chemistry, vol. 275, no. 12, pp. 8592-8599. https://doi.org/10.1074/jbc.275.12.8592
Mould, Jorgen A. ; Li, Hui Chun ; Dudlak, Christine S. ; Lear, James D. ; Pekosz, Andrew ; Lamb, Robert A. ; Pinto, Lawrence H. / Mechanism for proton conduction of the M2 ion channel of influenza A virus. In: Journal of Biological Chemistry. 2000 ; Vol. 275, No. 12. pp. 8592-8599.
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