Molecular mechanism of agonist recognition by the ligand-binding core of the ionotropic glutamate receptor 4
Kasper, C., Frydenvang, K., Naur, P., Gajhede, M., Pickering, D.S., Kastrup, J.S.(2008) FEBS Lett 582: 4089-4094
- PubMed: 19022251 
- DOI: https://doi.org/10.1016/j.febslet.2008.11.005
- Primary Citation of Related Structures:  
3FAS, 3FAT - PubMed Abstract: 
The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) class of ionotropic glutamate receptors comprises four different subunits: iGluR1/iGluR2 and iGluR3/iGluR4 forming two subgroups. Three-dimensional structures have been reported only of the ligand-binding core of iGluR2. Here, we present two X-ray structures of a soluble construct of the R/G unedited flip splice variant of the ligand-binding core of iGluR4 (iGluR4(i)(R)-S1S2) in complex with glutamate or AMPA. Subtle, but important differences are found in the ligand-binding cavity between the two AMPA receptor subgroups at position 724 (Tyr in iGluR1/iGluR2 and Phe in iGluR3/iGluR4), which in iGluR4 may lead to displacement of a water molecule and hence points to the possibility to make subgroup specific ligands.
Organizational Affiliation: 
Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.