Mapping of residues forming the voltage sensor of the voltage-dependent anion-selective channel

Lorie Thomas, Elizabeth Blachly-Dyson, Marco Colombini, Michael Forte

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Abstract

Voltage-gated ion-channel proteins contain "voltage-sensing" domains that drive the conformational transitions between open and closed states in response to changes in transmembrane voltage. We have used site-directed mutagenesis to identify residues affecting the voltage sensitivity of a mitochondrial channel, the voltage-dependent anion-selective channel (VDAC). Although charge changes at many sites had no effect, at other sites substitutions that increased positive charge also increased the steepness of voltage dependance and substitutions that decreased positive charge decreased voltage dependance by an appropriate amount. In contrast to the plasma membrane K+ and Na+ channels, these residues are distributed over large parts of the VDAC protein. These results have been used to define the conformational transitions that accompany voltage gating of an ion channel. This gating mechanism requires the movement of large portions of the VDAC protein through the membrane.

Original languageEnglish (US)
Pages (from-to)5446-5449
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume90
Issue number12
DOIs
StatePublished - Jun 15 1993

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Keywords

  • Mitochondrion
  • Outer membrane
  • Voltage gating
  • Yeast
  • β barrel

ASJC Scopus subject areas

  • General

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