Kcv from the chlorella virus PBCV-1 is a viral protein that forms a tetrameric, functional K+ channel in heterologous systems. Kcv can serve as a model system to study and manipulate basic properties of the K+ channel pore because its minimalistic structure (94 amino acids) produces basic features of ion channels, such as selectivity, gating, and sensitivity to blockers. We present a characterization of Kcv properties at the single-channel level. In symmetric 100 mM K+, single-channel conductance is 114 ± 11 pS. Two different voltage-dependent mechanisms are responsible for the gating of Kcv. “Fast” gating, analyzed by β distributions, is responsible for the negative slope conductance in the single-channel current–voltage curve at extreme potentials, like in MaxiK potassium channels, and can be explained by depletion-aggravated instability of the filter region. The presence of a “slow” gating is revealed by the very low (in the order of 1–4%) mean open probability that is voltage dependent and underlies the time-dependent component of the macroscopic current.
Fast and slow gating are inherent properties of the K+ channel pore module / A. Abenavoli, M.L. Di Francesco, I. Schroeder, S. Epimashko, S. Gazzarrini, U.P. Hansen, G. Thiel, A. Moroni. - In: JOURNAL OF GENERAL PHYSIOLOGY. - ISSN 0022-1295. - 134:3(2009 Aug 31), pp. 219-229.
|Titolo:||Fast and slow gating are inherent properties of the K+ channel pore module|
ABENAVOLI, ALESSANDRA (Primo)
DI FRANCESCO, MATTIA LORENZO (Secondo)
MORONI, ANNA (Ultimo)
|Parole Chiave:||MaxiK selectivity filter ; patch-clamp data ; potassium-channel ; chlorella viruses ; inactivation ; instability ; Chara ; state ; distributions ; spectroscopy|
|Settore Scientifico Disciplinare:||Settore BIO/04 - Fisiologia Vegetale|
|Data di pubblicazione:||31-ago-2009|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1085/jgp.200910266|
|Appare nelle tipologie:||01 - Articolo su periodico|