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Role of individual surface charges of voltage-gated K channels.

Authors
  • Elinder, F
  • Arhem, P
Type
Published Article
Journal
Biophysical journal
Publication Date
Sep 01, 1999
Volume
77
Issue
3
Pages
1358–1362
Identifiers
PMID: 10465747
Source
Medline
License
Unknown

Abstract

Fixed charges on the extracellular surface of voltage-gated ion channels influence the gating. In previous studies of cloned voltage-gated K channels, we found evidence that the functional surface charges are located on the peptide loop between the fifth transmembrane segment and the pore region (the S5-P loop). In the present study, we determine the role of individual charges of the S5-P loop by correlating primary structure with experimentally calculated surface potentials of the previously investigated channels. The results suggest that contributions to the surface potential at the voltage sensor of the different residues varies in an oscillating pattern, with the first residue of the N-terminal end of the S5-P loop, an absolutely conserved glutamate, contributing most. An analysis yields estimates of the distance between the residues and the voltage sensor, the first N-terminal residue being located at a distance of 5-6 A. To explain the results, a structural hypothesis, comprising an alpha-helical N-terminal end of the S5-P loop, is presented.

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