Three-dimensional structure of the S4-S5 segment of the Shaker potassium channel

Biophys J. 2002 Jun;82(6):2995-3002. doi: 10.1016/S0006-3495(02)75640-3.


The propagation of action potentials during neuronal signal transduction in phospholipid membranes is mediated by ion channels, a diverse group of membrane proteins. The S4-S5 linker peptide (S4-S5), that connects the S4 and S5 transmembrane segments of voltage-gated potassium channels is an important region of the Shaker ion-channel protein. Despite its importance, very little is known about its structure. Here we provide evidence for an amphipathic alpha-helical conformation of a synthetic S4-S5 peptide of the voltage-gated Drosophila melanogaster Shaker potassium channel in water/trifluoroethanol and in aqueous phospholipid micelles. The three-dimensional solution structures of the S4-S5 peptide were obtained by high-resolution nuclear magnetic resonance spectroscopy and distance-geometry/simulated-annealing calculations. The detailed structural features are discussed with respect to model studies and available mutagenesis data on the mechanism and selectivity of the potassium channel.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biophysical Phenomena
  • Biophysics
  • Drosophila Proteins / chemistry
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptide Fragments / chemistry
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Potassium Channels / chemistry*
  • Potassium Channels / genetics
  • Potassium Channels / metabolism
  • Protein Conformation
  • Protein Structure, Secondary
  • Shaker Superfamily of Potassium Channels


  • Drosophila Proteins
  • Peptide Fragments
  • Potassium Channels
  • Sh protein, Drosophila
  • Shaker Superfamily of Potassium Channels