Blockage of human T lymphocyte Kv1.3 channels by Pi1, a novel class of scorpion toxin

Mózes Péter, Péter Hajdu, Zoltán Varga, Sándor Damjanovich, Lourival D. Possani, György Panyi, Rezsö Gáspár

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Using the patch-clamp technique we determined that Pandinus imperator toxin Pi1, a recently described peptide toxin having four disulfide bridges instead of the usual three in scorpion toxins, blocked Kv1.3 channels of human T lymphocytes from the extracellular side with a 1:1 stoichiometry. Kv1.3 block was instantaneous and removable with toxin-free extracellular solution. The toxin did not influence activation or inactivation of the channels. We found that Pi1 blocked Kv1.3 with less affinity (K(d) = 11.4 nM) than the structurally related three disulfide bridge containing toxins Pi2 (50 pM) and Pi3 (0.5 nM). The fourth disulfide bridge in Pi1 had no influence on the channel binding ability of the toxin; the less effective block was due to differences in amino acid side chain properties at positions 11 and 35. (C) 2000 Academic Press.

Original languageEnglish
Pages (from-to)34-37
Number of pages4
JournalBiochemical and biophysical research communications
Issue number1
Publication statusPublished - Nov 11 2000


ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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