8R36

Crystal structure of the Gluk1 ligand-binding domain in complex with kainate and BPAM538 at 1.90 A resolution

Summary for 8R36

• Entry DOI: 10.2210/pdb8r36/pdb
• Descriptor: Glutamate receptor ionotropic, kainate 1, 3-(CARBOXYMETHYL)-4-ISOPROPENYLPROLINE, SULFATE ION, ... (7 entities in total)
• Functional Keywords: ionotropic glutamate receptor, gluk1 ligand-binding domain, membrane protein, positive allosteric modulator, kainate
• Biological source: Rattus norvegicus (Norway rat); More
• Total number of polymer chains: 2
• Total formula weight: 60026.02

Authors

Bay, Y.,Frantsen, S.M.,Frydenvang, K.,Kastrup, J.S. (deposition date: 2023-11-08, release date: 2024-08-14, Last modification date: 2024-10-23)

Primary citation

Bay, Y.,Cabello, F.J.M.,Koens, C.C.,Frantsen, S.M.,Pickering, D.S.,Frydenvang, K.,Francotte, P.,Pirotte, B.,Kristensen, A.S.,Bowie, D.,Kastrup, J.S.
Crystal structure of the GluK1 ligand-binding domain with kainate and the full-spanning positive allosteric modulator BPAM538.
J.Struct.Biol., 216:108113-108113, 2024

PubMed Abstract: Kainate receptors play an important role in the central nervous system by mediating postsynaptic excitatory neurotransmission and modulating the release of the inhibitory neurotransmitter GABA through a presynaptic mechanism. To date, only three structures of the ligand-binding domain (LBD) of the kainate receptor subunit GluK1 in complex with positive allosteric modulators have been determined by X-ray crystallography, all belonging to class II modulators. Here, we report a high-resolution structure of GluK1-LBD in complex with kainate and BPAM538, which belongs to the full-spanning class III. One BPAM538 molecule binds at the GluK1 dimer interface, thereby occupying two allosteric binding sites simultaneously. BPAM538 stabilizes the active receptor conformation with only minor conformational changes being introduced to the receptor. Using a calcium-sensitive fluorescence-based assay, a 5-fold potentiation of the kainate response (100 μM) was observed in presence of 100 μM BPAM538 at GluK1(Q), whereas no potentiation was observed at GluK2(VCQ). Using electrophysiology recordings of outside-out patches excised from HEK293 cells, BPAM538 increased the peak response of GluK1(Q) co-expressed with NETO2 to rapid application of 10 mM L-glutamate with 130 ± 20 %, and decreased desensitization determined as the steady-state/peak response ratio from 23 ± 2 % to 90 ± 4 %. Based on dose-response relationship experiments on GluK1(Q) the EC of BPAM538 was estimated to be 57.5 ± 29.2 μM.

PubMed: 39079583
DOI: 10.1016/j.jsb.2024.108113

Experimental method

X-RAY DIFFRACTION (1.9 Å)