S3b amino acid residues do not shuttle across the bilayer in voltage-dependent Shaker K+ channels
Author
dc.contributor.author
Gonzalez, Carlos
Author
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Morera, Francisco J.
Author
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Rosenmann, Eduardo
Author
dc.contributor.author
Alvarez, Osvaldo
Author
dc.contributor.author
Latorre, Ramón
Admission date
dc.date.accessioned
2018-12-20T14:10:48Z
Available date
dc.date.available
2018-12-20T14:10:48Z
Publication date
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2005
Cita de ítem
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Proceedings of the National Academy of Sciences of the United States of America, Volumen 102, Issue 14, 2018, Pages 5020-5025
Identifier
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00278424
Identifier
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10.1073/pnas.0501051102
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/154440
Abstract
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In voltage-dependent channels, positive charges contained within the S4 domain are the voltage-sensing elements. The "voltage-sensor paddle" gating mechanism proposed for the KvAP K+ channel has been the subject of intense discussion regarding its general applicability to the family of voltage-gated channels. In this model, the voltage sensor composed of the S3b and the S4 segment shuttles across the lipid bilayer during channel activation. Guided by this mechanism, we assessed here the accessibility of residues in the S3 segment of the Shaker K+ channel by using cysteine-scanning mutagenesis. Mutants expressed robust K+ currents in Xenopus oocytes and reacted with methanethiosulfonate ethyltrimethylammonium in both closed and open conformations of the channel. Because Shaker has a long S3-S4 linker segment, we generated a deletion mutant with only three residues to emulate the KvAP structure. In this short linker mutant, all of the tested residues in the S3b were accessible to methane