Purified, modified eel sodium channels are active in planar bilayers in the absence of activating neurotoxins

S. Shenkel, E. C. Cooper, W. James, W. S. Agnew, F. J. Sigworth

Research output: Contribution to journalArticlepeer-review

Abstract

A recent study showed that limited trypsin treatment of liposomes containing purified Electrophorus electricus sodium channels activates a sodium radiotracer flux. We now report that similarly treated sodium channels show voltage-gated, tetrodotoxin-sensitive and highly sodium-selective single-channel currents when incorporated into planar lipid membranes. The trypsinized channels opened repeatedly in bursts of several seconds duration, as would be expected for channels whose fast inactivation process had been removed. Furthermore, they have a higher conductance, different voltage-dependence of gating, and a remarkably higher selectivity (P(Na)/P(K) = 41) than sodium channels bound by batrachotoxin or other activating neurotoxins; these properties of the trypsinized channels are probably closer to those of channels in intact electrocytes.

Original languageEnglish (US)
Pages (from-to)9592-9596
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume86
Issue number23
DOIs
StatePublished - 1989

Keywords

  • batrachotoxin
  • electrocytes
  • ion channels
  • ion selectivity
  • trypsin

ASJC Scopus subject areas

  • General

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