Selectivity filter mutations shift ion permeation mechanism in potassium channels.

ABSTRACT: Potassium (K⁺) channels combine high conductance with high ion selectivity. To explain this efficiency, two molecular mechanisms have been proposed. The "direct knock-on" mechanism is defined by water-free K⁺ permeation and formation of direct ion-ion contacts in the highly conserved selectivity filter (SF). The "soft knock-on" mechanism involves co-permeation of water and separation of K⁺ by water molecules. With the aim to distinguish between these mechanisms, crystal structures of the KcsA channel with mutations in two SF residues-G77 and T75-were published, where the arrangements of K⁺ ions and water display canonical soft knock-on configurations. These data were interpreted as evidence of the soft knock-on mechanism in wild-type channels. He

SUBMITTER: Mironenko A 

PROVIDER: S-EPMC11251424 | biostudies-literature | 2024 Jul

REPOSITORIES: biostudies-literature