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Na+ block and permeation in a K+ channel of known structure.

TitleNa+ block and permeation in a K+ channel of known structure.
Publication TypeJournal Article
Year of Publication2002
AuthorsNimigean CM, Miller C
JournalJ Gen Physiol
Volume120
Issue3
Pagination323-35
Date Published2002 Sep
ISSN0022-1295
KeywordsBacterial Proteins, Cell Membrane Permeability, Ion Channel Gating, Lipid Bilayers, Membrane Potentials, Membranes, Artificial, Potassium Channels, Sodium
Abstract

The effects of intracellular Na(+) were studied on K(+) and Rb(+) currents through single KcsA channels. At low voltage, Na(+) produces voltage-dependent block, which becomes relieved at high voltage by a "punchthrough" mechanism representing Na(+) escaping from its blocking site through the selectivity filter. The Na(+) blocking site is located in the wide, hydrated vestibule, and it displays unexpected selectivity for K(+) and Rb(+) against Na(+). The voltage dependence of Na(+) block reflects coordinated movements of the blocker with permeant ions in the selectivity filter.

Alternate JournalJ. Gen. Physiol.
PubMed ID12198089
PubMed Central IDPMC2229518
Grant ListGM-31867 / GM / NIGMS NIH HHS / United States