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Gating of the designed trimeric/tetrameric voltage-gated H+ channel.
Fujiwara, Yuichiro; Kurokawa, Tatsuki; Takeshita, Kohei; Nakagawa, Atsushi; Larsson, H Peter; Okamura, Yasushi.
Afiliação
  • Fujiwara Y; Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan. fujiwara@phys2.med.osaka-u.ac.jp
J Physiol ; 591(3): 627-40, 2013 Feb 01.
Article em En | MEDLINE | ID: mdl-23165764
ABSTRACT
The voltage-gated H(+) channel functions as a dimer, a configuration that is different from standard tetrameric voltage-gated channels. Each channel protomer has its own permeation pathway. The C-terminal coiled-coil domain has been shown to be necessary for both dimerization and cooperative gating in the two channel protomers. Here we report the gating cooperativity in trimeric and tetrameric Hv channels engineered by altering the hydrophobic core sequence of the coiled-coil assembly domain. Trimeric and tetrameric channels exhibited more rapid and less sigmoidal kinetics of activation of H(+) permeation than dimeric channels, suggesting that some channel protomers in trimers and tetramers failed to produce gating cooperativity observed in wild-type dimers. Multimerization of trimer and tetramer channels were confirmed by the biochemical analysis of proteins, including crystallography. These findings indicate that the voltage-gated H(+) channel is optimally designed as a dimeric channel on a solid foundation of the sequence pattern of the coiled-coil core, with efficient cooperative gating that ensures sustained and steep voltage-dependent H(+) conductance in blood cells.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Ativação do Canal Iônico / Canais Iônicos Limite: Humans Idioma: En Ano de publicação: 2013 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Ativação do Canal Iônico / Canais Iônicos Limite: Humans Idioma: En Ano de publicação: 2013 Tipo de documento: Article