Mechanism of activation at the selectivity filter of the KcsA K+ channel.
Elife
; 62017 10 10.
Article
em En
| MEDLINE
| ID: mdl-28994652
ABSTRACT
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Potássio
/
Proteínas de Bactérias
/
Canais de Potássio de Abertura Dependente da Tensão da Membrana
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article