Enhanced closed-state inactivation in a mutant Shaker K+ channel.
J Membr Biol
; 157(3): 215-30, 1997 Jun 01.
Article
em En
| MEDLINE
| ID: mdl-9178609
ABSTRACT
Many mutations that shift the voltage dependence of activation in Shaker channels cause a parallel shift of inactivation. The I2 mutation (L382I in the Shaker B sequence) is an exception, causing a 45 mV activation shift with only a 9 mV shift of inactivation midpoint relative to the wildtype (WT) channel. We compare the behavior of WT and I2 Shaker 29-4 channels in macropatch recordings from Xenopus oocytes. The behavior of WT channels can be described by both simple and detailed kinetic models which assume that inactivation proceeds only from the open state. The behavior of I2 channels requires that they inactivate from closed states as well, a property characteristic of voltage-gated sodium channels. A detailed "multiple-state inactivation" model is presented that describes both activation and inactivation of I2 channels. The results are consistent with the view that residue L382 is associated with the receptor for the inactivation particles in Shaker channels.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Canais de Potássio
/
Ativação do Canal Iônico
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Membr Biol
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Estados Unidos
País de publicação:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA