TU Darmstadt / ULB / TUbiblio

Electrokinetics of miniature K+ channel: open-state V sensitivity and inhibition by K+ driving force.

Gazzarrini, Sabrina and Abenavoli, Alessandra and Gradmann, Dietrich and Thiel, Gerhard and Moroni, Anna :
Electrokinetics of miniature K+ channel: open-state V sensitivity and inhibition by K+ driving force.
In: The Journal of membrane biology, 214 (1) pp. 9-17. ISSN 0022-2631
[Article] , (2006)

Abstract

Kcv, isolated from a Chlorella virus, is the smallest known K+ channel. When Kcv is expressed in Xenopus oocytes and exposed to 50 mM: [K+](o), its open-state current-voltage relationship (I-V) has the shape of a "tilted S" between -200 and +120 mV. Details of this shape depend on the conditioning voltage (V (c)) immediately before an I-V recording. Unexpectedly, the I-V relationships, recorded in different [K+](o), do intersect. These characteristics are numerically described here by fits of a kinetic model to the experimental data. In this model, the V (c) sensitivity of I-V is mainly assigned to an affinity increase of external K+ association at more positive voltages. The general, tilted-S shape as well as the unexpected intersections of the I-V relationships are kinetically described by a decrease of the cord conductance by the electrochemical driving force for K+ in either direction, like in fast V-dependent blocking by competing ions.

Item Type: Article
Erschienen: 2006
Creators: Gazzarrini, Sabrina and Abenavoli, Alessandra and Gradmann, Dietrich and Thiel, Gerhard and Moroni, Anna
Title: Electrokinetics of miniature K+ channel: open-state V sensitivity and inhibition by K+ driving force.
Language: English
Abstract:

Kcv, isolated from a Chlorella virus, is the smallest known K+ channel. When Kcv is expressed in Xenopus oocytes and exposed to 50 mM: [K+](o), its open-state current-voltage relationship (I-V) has the shape of a "tilted S" between -200 and +120 mV. Details of this shape depend on the conditioning voltage (V (c)) immediately before an I-V recording. Unexpectedly, the I-V relationships, recorded in different [K+](o), do intersect. These characteristics are numerically described here by fits of a kinetic model to the experimental data. In this model, the V (c) sensitivity of I-V is mainly assigned to an affinity increase of external K+ association at more positive voltages. The general, tilted-S shape as well as the unexpected intersections of the I-V relationships are kinetically described by a decrease of the cord conductance by the electrochemical driving force for K+ in either direction, like in fast V-dependent blocking by competing ions.

Journal or Publication Title: The Journal of membrane biology
Volume: 214
Number: 1
Divisions: 10 Department of Biology > Plant Membrane Biophysics
?? fb10_botanik ??
10 Department of Biology
Date Deposited: 22 Jun 2011 07:22
Export:

Optionen (nur für Redakteure)

View Item View Item