Multiple subunits of a voltage-dependent potassium channel contribute to the binding site for tetraethylammonium

Neuron. 1992 Mar;8(3):493-7. doi: 10.1016/0896-6273(92)90277-k.


RNAs encoding a wild-type (RBK1) and a mutant (RBK1(Y379V,V381T); RBK1*) subunit of voltage-dependent potassium channels were injected into Xenopus oocytes. When expressed separately, they made homotetrameric channels that differed about 100-fold in sensitivity to tetraethylammonium (TEA). Mixtures of channels having one, two, or three low affinity subunits were expressed by injecting various proportions of RBK1 and RBK1* RNAs. The affinity for TEA of these three channel species was deduced by fitting concentration-response curves for the inhibition of potassium currents. DNAs were also concatenated to construct a sequence that encoded two connected subunits, and channels that contained four, two, or no TEA-sensitive subunits were expressed. The results suggest that bound TEA interacts simultaneously with all four subunits.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Binding Sites
  • In Vitro Techniques
  • Macromolecular Substances
  • Membrane Potentials
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Oligodeoxyribonucleotides / chemistry
  • Oocytes
  • Potassium Channels / metabolism*
  • Recombinant Proteins / metabolism
  • Structure-Activity Relationship
  • Tetraethylammonium Compounds / metabolism*
  • Xenopus laevis


  • Macromolecular Substances
  • Oligodeoxyribonucleotides
  • Potassium Channels
  • Recombinant Proteins
  • Tetraethylammonium Compounds