Glycine 30 in iberiotoxin is a critical determinant of its specificity for maxi-K versus KV channels

Nathan Schroeder, Theodore J. Mullmann, W. A. Schmalhofer, Ying Duo Gao, Maria L. Garcia, Kathleen M. Giangiacomo

Research output: Contribution to journalArticlepeer-review

Abstract

Iberiotoxin (IbTX) is a remarkably selective α-K toxin peptide (α-KTx) inhibitor of the maxi-K channel. In contrast, the highly homologous charybdotoxin inhibits both the maxi-K and KV1.3 channels with similar high affinity. The present study investigates the molecular basis for this specificity through mutagenesis of IbTX. The interactions of mutated peptides with maxi-K and KV1.3 channels were monitored through dose-dependent displacement of specifically bound iodinated α-KTx peptides from membranes expressing these channels. Results of these studies suggest that the presence of a glycine at position 30 in IbTX is a major determinant of its specificity while the presence of four unique acidic residues in IbTX is not.

Original languageEnglish (US)
Pages (from-to)298-302
Number of pages5
JournalFEBS Letters
Volume527
Issue number1-3
DOIs
StatePublished - Sep 11 2002
Externally publishedYes

Keywords

  • α-K peptide
  • Charybdotoxin
  • Iberiotoxin
  • K1.3 channel
  • Maxi-K channel

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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