Free RCK arrangement in Kch, a putative escherichia coli potassium channel, as suggested by electron crystallography

Structure. 2015 Jan 6;23(1):199-205. doi: 10.1016/j.str.2014.10.018. Epub 2014 Dec 11.


The ligand-gated potassium channels are stimulated by various kinds of messengers. Previous studies showed that ligand-gated potassium channels containing RCK domains (the regulator of the conductance of potassium ion) form a dimer of tetramer structure through the RCK octameric gating ring in the presence of detergent. Here, we have analyzed the structure of Kch, a channel of this type from Escherichia coli, in a lipid environment using electron crystallography. By combining information from the 3D map of the transmembrane part of the protein and docking of an atomic model of a potassium channel, we conclude that the RCK domains face the solution and that an RCK octameric gating ring arrangement does not form under our crystallization condition. Our findings may be applied to other potassium channels that have an RCK gating ring arrangement.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography
  • Crystallography, X-Ray
  • Escherichia coli Proteins / chemistry*
  • Ion Channel Gating
  • Lipids / pharmacology
  • Microscopy, Electron
  • Models, Molecular
  • Molecular Docking Simulation
  • Potassium Channels / chemistry*
  • Protein Interaction Maps
  • Protein Structure, Quaternary / drug effects
  • Protein Structure, Tertiary / drug effects


  • Escherichia coli Proteins
  • Lipids
  • Potassium Channels
  • kch protein, E coli