The Three-dimensional Structure of an Ionotropic Glutamate Receptor Reveals a Dimer-of-dimers Assembly.
J Mol Biol
; 344(2): 435-42, 2004 Nov 19.
Article
em En
| MEDLINE
| ID: mdl-15522296
ABSTRACT
The ionotropic glutamate receptors (iGluRs) represent a major family of ion channels whose quaternary structure has not yet been defined. Here, we present the three-dimensional structure of a fully assembled iGluR, determined at approximately 20A resolution by electron microscopy. Analysis of negatively stained single-particle images reveals the presence of 2-fold, but not 4-fold, symmetry for these tetrameric channels, providing the first direct structural evidence for a dimer-of-dimers assembly. The receptor appears elongated, measuring approximately 170Ax140Ax110A, with the 2-fold symmetry centered on its longitudinal axis. The overall molecular shape and symmetry suggest an orientation relative to the membrane and permit the identification of a putative transmembrane domain. Internal cavities located along the longitudinal axis may represent components of the ion conduction pathway.
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Base de dados:
MEDLINE
Assunto principal:
Receptores de Glutamato
/
Dimerização
/
Canais Iônicos
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article