Molecular architecture of the KvAP voltage-dependent K+ channel in a lipid bilayer

Science. 2004 Oct 15;306(5695):491-5. doi: 10.1126/science.1101373.


We have analyzed the local structure and dynamics of the prokaryotic voltage-dependent K+ channel (KvAP) at 0 millivolts, using site-directed spin labeling and electron paramagnetic resonance spectroscopy. We show that the S4 segment is located at the protein/lipid interface, with most of its charges protected from the lipid environment. Structurally, S4 is highly dynamic and is separated into two short helices by a flexible linker. Accessibility and dynamics data indicate that the S1 segment is surrounded by other parts of the protein. We propose that S1 is at the contact interface between the voltage-sensing and pore domains. These results establish the general principles of voltage-dependent channel structure in a biological membrane.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Electron Spin Resonance Spectroscopy
  • Hydrophobic and Hydrophilic Interactions
  • Lipid Bilayers*
  • Models, Molecular
  • Oxygen
  • Potassium Channels, Voltage-Gated / chemistry*
  • Potassium Channels, Voltage-Gated / metabolism*
  • Protein Conformation
  • Protein Structure, Secondary
  • Protein Structure, Tertiary


  • Lipid Bilayers
  • Potassium Channels, Voltage-Gated
  • Oxygen