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Creation of a reactive oxygen species-insensitive Kcv channel.

Schroeder, Indra and Gazzarrini, Sabrina and Ferrara, Giuseppina and Thiel, Gerhard and Hansen, Ulf-Peter and Moroni, Anna (2013):
Creation of a reactive oxygen species-insensitive Kcv channel.
In: Biochemistry, pp. 3130-7, 52, (18), ISSN 1520-4995,
[Article]

Abstract

The current of the minimal viral K(+) channel Kcv(PCBV-1) heterologously expressed in Xenopus oocytes is strongly inhibited by reactive oxygen species (ROS) like H(2)O(2). Possible targets for the ROS effect are two cysteines (C53 and C79) and four methionines (M1, M15, M23, and M26). The C53A/C79A and M23L/M26L double mutations maintained the same ROS sensitivity as the wild type. However, M15L as a single mutant or in combination with C53A/C79A and/or M23L/M26L caused a complete loss of sensitivity to H(2)O(2). These results indicate a prominent role of M15 at the cytosolic end of the outer transmembrane helix for gating of Kcv(PCBV-1). Furthermore, even though the channel lacks a canonical voltage sensor, it exhibits a weak voltage sensitivity, resulting in a slight activation in the millisecond range after a voltage step to negative potentials. The M15L mutation inverts this kinetics into an inactivation, underlining the critical role of this residue for gating. The negative slope of the I-V curves of M15L is the same as in the wild type, indicating that the selectivity filter is not involved.

Item Type: Article
Erschienen: 2013
Creators: Schroeder, Indra and Gazzarrini, Sabrina and Ferrara, Giuseppina and Thiel, Gerhard and Hansen, Ulf-Peter and Moroni, Anna
Title: Creation of a reactive oxygen species-insensitive Kcv channel.
Language: English
Abstract:

The current of the minimal viral K(+) channel Kcv(PCBV-1) heterologously expressed in Xenopus oocytes is strongly inhibited by reactive oxygen species (ROS) like H(2)O(2). Possible targets for the ROS effect are two cysteines (C53 and C79) and four methionines (M1, M15, M23, and M26). The C53A/C79A and M23L/M26L double mutations maintained the same ROS sensitivity as the wild type. However, M15L as a single mutant or in combination with C53A/C79A and/or M23L/M26L caused a complete loss of sensitivity to H(2)O(2). These results indicate a prominent role of M15 at the cytosolic end of the outer transmembrane helix for gating of Kcv(PCBV-1). Furthermore, even though the channel lacks a canonical voltage sensor, it exhibits a weak voltage sensitivity, resulting in a slight activation in the millisecond range after a voltage step to negative potentials. The M15L mutation inverts this kinetics into an inactivation, underlining the critical role of this residue for gating. The negative slope of the I-V curves of M15L is the same as in the wild type, indicating that the selectivity filter is not involved.

Journal or Publication Title: Biochemistry
Volume: 52
Number: 18
Divisions: 10 Department of Biology
10 Department of Biology > Plant Membrane Biophysics
Date Deposited: 25 Jun 2013 12:26
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