Pharmacological and structural characterization of conformationally restricted (S)-glutamate analogues at ionotropic glutamate receptors

TY - JOUR

T1 - Pharmacological and structural characterization of conformationally restricted (S)-glutamate analogues at ionotropic glutamate receptors

AU - Juknaite, Lina

AU - Venskutonyte, Raminta

AU - Assaf, Zeinab

AU - Faure, Sophie

AU - Gefflaut, Thierry

AU - Aitken, David J.

AU - Nielsen, Birgitte

AU - Gajhede, Michael

AU - Kastrup, Jette Sandholm Jensen

AU - Bunch, Lennart

AU - Frydenvang, Karla

AU - Pickering, Darryl S.

N1 - Copyright © 2012. Published by Elsevier Inc.

PY - 2012/10

Y1 - 2012/10

N2 - Conformationally restricted glutamate analogues have been pharmacologically characterized at AMPA and kainate receptors and the crystal structures have been solved of the ligand (2S,1'R,2'S)-2-(2'-carboxycyclobutyl)glycine (CBG-IV) in complex with the ligand binding domains of the AMPA receptor GluA2 and the kainate receptor GluK3. These structures show that CBG-IV interacts with the binding pocket in the same way as (S)-glutamate. The binding affinities reveal that CBG-IV has high affinity at the AMPA and kainate receptor subtypes. Appreciable binding affinity of CBG-IV was not observed at NMDA receptors, where the introduction of the carbocyclic ring is expected to lead to a steric clash with binding site residues. CBG-IV was demonstrated to be an agonist at both GluA2 and the kainate receptor GluK1. CBG-IV showed high affinity binding to GluK1 compared to GluA2, GluK2 and GluK3, which exhibited lower affinity for CBG-IV. The structure of GluA2 LBD and GluK3 LBD in complex with CBG-IV revealed similar binding site interactions to those of (S)-glutamate. No major conformational rearrangements compared to the (S)-glutamate bound conformation were found in GluK3 in order to accommodate CBG-IV, in contrast with GluA2 where a shift in lobe D2 binding site residues occurs, leading to an increased binding cavity volume compared to the (S)-glutamate bound structure.

AB - Conformationally restricted glutamate analogues have been pharmacologically characterized at AMPA and kainate receptors and the crystal structures have been solved of the ligand (2S,1'R,2'S)-2-(2'-carboxycyclobutyl)glycine (CBG-IV) in complex with the ligand binding domains of the AMPA receptor GluA2 and the kainate receptor GluK3. These structures show that CBG-IV interacts with the binding pocket in the same way as (S)-glutamate. The binding affinities reveal that CBG-IV has high affinity at the AMPA and kainate receptor subtypes. Appreciable binding affinity of CBG-IV was not observed at NMDA receptors, where the introduction of the carbocyclic ring is expected to lead to a steric clash with binding site residues. CBG-IV was demonstrated to be an agonist at both GluA2 and the kainate receptor GluK1. CBG-IV showed high affinity binding to GluK1 compared to GluA2, GluK2 and GluK3, which exhibited lower affinity for CBG-IV. The structure of GluA2 LBD and GluK3 LBD in complex with CBG-IV revealed similar binding site interactions to those of (S)-glutamate. No major conformational rearrangements compared to the (S)-glutamate bound conformation were found in GluK3 in order to accommodate CBG-IV, in contrast with GluA2 where a shift in lobe D2 binding site residues occurs, leading to an increased binding cavity volume compared to the (S)-glutamate bound structure.

U2 - 10.1016/j.jsb.2012.07.001

DO - 10.1016/j.jsb.2012.07.001

M3 - Journal article

C2 - 22789682

SN - 1047-8477

VL - 180

SP - 39

EP - 46

JO - Journal of Structural Biology

JF - Journal of Structural Biology

IS - 1

ER -