Structural highlights
FunctionMTHK_METTH Calcium-gated potassium channel. Publication Abstract from PubMedUnderstanding how ion channels open and close their pores is crucial for comprehending their physiological roles. We used intracellular quaternary ammonium blockers, electrophysiology and X-ray crystallography to locate the voltage-dependent gate in MthK potassium channels from Methanobacterium thermoautotrophicum. Blockers bind in an aqueous cavity between two putative gates: an intracellular gate and the selectivity filter. Thus, these blockers directly probe gate location-an intracellular gate will prevent binding when closed, whereas a selectivity filter gate will always allow binding. Kinetic analysis of tetrabutylammonium block of single MthK channels combined with X-ray crystallographic analysis of the pore with tetrabutyl antimony unequivocally determined that the voltage-dependent gate, like the C-type inactivation gate in eukaryotic channels, is located at the selectivity filter. State-dependent binding kinetics suggest that MthK inactivation leads to conformational changes within the cavity and intracellular pore entrance. The voltage-dependent gate in MthK potassium channels is located at the selectivity filter.,Posson DJ, McCoy JG, Nimigean CM Nat Struct Mol Biol. 2013 Feb;20(2):159-66. doi: 10.1038/nsmb.2473. Epub 2012 Dec, 23. PMID:23262489[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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