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Chlorella virus ATCV-1 encodes a functional potassium channel of 82 amino acids.

Gazzarrini, Sabrina and Kang, Ming and Abenavoli, Alessandra and Romani, Giulia and Olivari, Claudio and Gaslini, Daniele and Ferrara, Giuseppina and Van Etten, James L. and Kreim, Michael and Kast, Stefan M. and Thiel, Gerhard and Moroni, Anna (2009):
Chlorella virus ATCV-1 encodes a functional potassium channel of 82 amino acids.
In: The Biochemical journal, pp. 295-303, 420, (2), ISSN 1470-8728,
[Article]

Abstract

Chlorella virus PBCV-1 (Paramecium bursaria chlorella virus-1) encodes the smallest protein (94 amino acids, named Kcv) previously known to form a functional K+ channel in heterologous systems. In this paper, we characterize another chlorella virus encoded K+ channel protein (82 amino acids, named ATCV-1 Kcv) that forms a functional channel in Xenopus oocytes and rescues Saccharomyces cerevisiae mutants that lack endogenous K+ uptake systems. Compared with the larger PBCV-1 Kcv, ATCV-1 Kcv lacks a cytoplasmic N-terminus and has a reduced number of charged amino acids in its turret domain. Despite these deficiencies, ATCV-1 Kcv accomplishes all the major features of K+ channels: it assembles into a tetramer, is K+ selective and is inhibited by the canonical K+ channel blockers, barium and caesium. Single channel analyses reveal a stochastic gating behaviour and a voltage-dependent conductance that resembles the macroscopic I/V relationship. One difference between PBCV-1 and ATCV-1 Kcv is that the latter is more permeable to K+ than Rb+. This difference is partially explained by the presence of a tyrosine residue in the selective filter of ATCV-1 Kcv, whereas PBCV-1 Kcv has a phenylalanine. Hence, ATCV-1 Kcv is the smallest protein to form a K+ channel and it will serve as a model for studying structure-function correlations inside the potassium channel pore.

Item Type: Article
Erschienen: 2009
Creators: Gazzarrini, Sabrina and Kang, Ming and Abenavoli, Alessandra and Romani, Giulia and Olivari, Claudio and Gaslini, Daniele and Ferrara, Giuseppina and Van Etten, James L. and Kreim, Michael and Kast, Stefan M. and Thiel, Gerhard and Moroni, Anna
Title: Chlorella virus ATCV-1 encodes a functional potassium channel of 82 amino acids.
Language: English
Abstract:

Chlorella virus PBCV-1 (Paramecium bursaria chlorella virus-1) encodes the smallest protein (94 amino acids, named Kcv) previously known to form a functional K+ channel in heterologous systems. In this paper, we characterize another chlorella virus encoded K+ channel protein (82 amino acids, named ATCV-1 Kcv) that forms a functional channel in Xenopus oocytes and rescues Saccharomyces cerevisiae mutants that lack endogenous K+ uptake systems. Compared with the larger PBCV-1 Kcv, ATCV-1 Kcv lacks a cytoplasmic N-terminus and has a reduced number of charged amino acids in its turret domain. Despite these deficiencies, ATCV-1 Kcv accomplishes all the major features of K+ channels: it assembles into a tetramer, is K+ selective and is inhibited by the canonical K+ channel blockers, barium and caesium. Single channel analyses reveal a stochastic gating behaviour and a voltage-dependent conductance that resembles the macroscopic I/V relationship. One difference between PBCV-1 and ATCV-1 Kcv is that the latter is more permeable to K+ than Rb+. This difference is partially explained by the presence of a tyrosine residue in the selective filter of ATCV-1 Kcv, whereas PBCV-1 Kcv has a phenylalanine. Hence, ATCV-1 Kcv is the smallest protein to form a K+ channel and it will serve as a model for studying structure-function correlations inside the potassium channel pore.

Journal or Publication Title: The Biochemical journal
Volume: 420
Number: 2
Divisions: 10 Department of Biology
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10 Department of Biology > Plant Membrane Biophysics
Date Deposited: 21 Jun 2011 12:06
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