Molecular Movement of the Voltage Sensor in a K Channel

Amir Broomand, Roope Männikkö, H. Peter Larsson, Fredrik Elinder

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


The X-ray crystallographic structure of KvAP, a voltage-gated bacterial K channel, was recently published. However, the position and the molecular movement of the voltage sensor, S4, are still controversial. For example, in the crystallographic structure, S4 is located far away (>30 Å) from the pore domain, whereas electrostatic experiments have suggested that S4 is located close (<8 Å) to the pore domain in open channels. To test the proposed location and motion of S4 relative to the pore domain, we induced disulphide bonds between pairs of introduced cysteines: one in S4 and one in the pore domain. Several residues in S4 formed a state-dependent disulphide bond with a residue in the pore domain. Our data suggest that S4 is located close to the pore domain in a neighboring subunit. Our data also place constraints on possible models for S4 movement and are not compatible with a recently proposed KvAP model.

Original languageEnglish (US)
Pages (from-to)741-748
Number of pages8
JournalJournal of General Physiology
Issue number6
StatePublished - Dec 2003
Externally publishedYes


  • Disulfide
  • Helical screw
  • S4 movement
  • Shaker K channel
  • Voltage gated

ASJC Scopus subject areas

  • Physiology


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