National Center for
3FAS: X-ray Structure of Iglur4 Flip Ligand-binding Core (S1s2) in Complex With (S)-glutamate at 1.40a Resolution
Molecular mechanism of agonist recognition by the ligand-binding core of the ionotropic glutamate receptor 4
FEBS Lett. (2008) 582 p.4089-4094
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.