Mechanism of activation at the selectivity filter of the KcsA K+channel Academic Article uri icon


MeSH Major

  • Calcium
  • Methanobacterium
  • Potassium Channels


  • Potassium channels are opened by ligands and/or membrane potential. In voltage-gated K+ channels and the prokaryotic KcsA channel, conduction is believed to result from opening of an intracellular constriction that prevents ion entry into the pore. On the other hand, numerous ligand-gated K+ channels lack such gate, suggesting that they may be activated by a change within the selectivity filter, a narrow region at the extracellular side of the pore. Using molecular dynamics simulations and electrophysiology measurements, we show that ligand-induced conformational changes in the KcsA channel removes steric restraints at the selectivity filter, thus resulting in structural fluctuations, reduced K+ affinity, and increased ion permeation. Such activation of the selectivity filter may be a universal gating mechanism within K+ channels. The occlusion of the pore at the level of the intracellular gate appears to be secondary.

publication date

  • October 10, 2017



  • Academic Article



  • eng

PubMed Central ID

  • PMC5669632

Digital Object Identifier (DOI)

  • 10.7554/eLife.25844

PubMed ID

  • 28994652

Additional Document Info


  • 6