Conductance selectivity of Na⁺ across the K⁺ channel via Na⁺ trapped in a tortuous trajectory.

ABSTRACT: Ion selectivity of the potassium channel is crucial for regulating electrical activity in living cells; however, the mechanism underlying the potassium channel selectivity that favors large K⁺ over small Na⁺ remains unclear. Generally, Na⁺ is not completely excluded from permeation through potassium channels. Herein, the distinct nature of Na⁺ conduction through the prototypical KcsA potassium channel was examined. Single-channel current recordings revealed that, at a high Na⁺ concentration (200 mM), the channel was blocked by Na⁺, and this blocking was relieved at high membrane potentials, suggesting the passage of Na⁺ across the channel. At a 2,000 mM Na⁺ concentration, single-channel Na⁺ c

SUBMITTER: Mita K 

PROVIDER: S-EPMC8000460 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature