The Three-dimensional Structure of an Ionotropic Glutamate Receptor Reveals a Dimer-of-dimers Assembly
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- 作者：Tichelaar ; Willem ; Safferling ; Markus ; Keinä ; nen ; Kari ; Stark ; Holger ; Madden ; Dean R.
- 关键词：ionotropic glutamate receptor ; AMPA receptor ; GluRB ; ion channel gating ; electron microscopy ; iGluRs ; ionotropic glutamate receptors ; NTD ; N-terminal domain ; LBD ; ligand-binding domain ; ER ; endoplasmic reticulum ; MRA ; multi-reference alignment ; MSA ; multi
- 刊名：Journal of Molecular Biology
- 出版年：2004
- 出版时间：November 19, 2004
- 年：2004
- 卷：344
- 期：2
- 页码：435-442
- 全文大小：428 K
文摘
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 
20Å 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 170Å×140Å×110Å, 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.
20Å 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 170Å×140Å×110Å, 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.