Adjacent pore-lining residues within sodium channels identified by paired cysteine mutagenesis

Jean Pierre Bénitah, Gordon F. Tomaselli, Eduardo Marban

Research output: Contribution to journalArticle

Abstract

The pores of voltage-gated ion channels are lined by protein loops that determine selectivity and conductance. The relative orientations of these 'P' loops remain uncertain, as do the distances between them. Using site-directed mutagenesis, we introduced pairs of cysteines into the P loops of μ1 rat skeletal muscle sodium channels and sought functional evidence of proximity between the substituted residues. Only cysteinyl residues that are in close proximity can form disulfide bonds or metal-chelating sites. The mutant Y401C (domain I) spontaneously formed a disulfide bond when paired with E758C in the P loop of domain II; the same residue, when coupled with G1530C in domain IV, created a high-affinity binding site for Cd2+ ions. The results provide the first specific constraints for intramolecular dimensions of the sodium channel pore.

Original languageEnglish (US)
Pages (from-to)7392-7396
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume93
Issue number14
DOIs
StatePublished - Jul 9 1996

ASJC Scopus subject areas

  • Genetics
  • General

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