Tetrameric assembly of KvLm K+ channels with defined numbers of voltage sensors

Ruhma Syeda, Jose S. Santos, Mauricio Montal, Hagan Bayley

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Voltage-gated K+ (Kv) channels are tetrameric assemblies in which each modular subunit consists of a voltage sensor and a pore domain. KvLm, the voltage-gated K+ channel from Listeria monocytogenes, differs from other Kv channels in that its voltage sensor contains only three out of the eight charged residues previously implicated in voltage gating. Here, we ask how many sensors are required to produce a functional Kv channel by investigating heterotetramers comprising combinations of full-length KvLm (FL) and its sensorless pore module. KvLm heterotetramers were produced by cell-free expression, purified by electrophoresis, and shown to yield functional channels after reconstitution in droplet interface bilayers. We studied the properties of KvLm channels with zero, one, two, three, and four voltage sensors. Three sensors suffice to promote channel opening with FL4-like voltage dependence at depolarizing potentials, but all four sensors are required to keep the channel closed during membrane hyperpolarization.

Original languageEnglish (US)
Pages (from-to)16917-16922
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number42
DOIs
StatePublished - Oct 16 2012

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Keywords

  • Lipid bilayers
  • Membrane proteins
  • Membrane reconstitution
  • Voltage gated potassium channels

ASJC Scopus subject areas

  • General

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