Binding of a negative allosteric modulator and competitive antagonist can occur simultaneously at the ionotropic glutamate receptor GluA2

TY - JOUR

T1 - Binding of a negative allosteric modulator and competitive antagonist can occur simultaneously at the ionotropic glutamate receptor GluA2

AU - Krintel, Christian

AU - Dorosz, Jerzy

AU - Larsen, Andreas Haahr

AU - Thorsen, Thor Seneca

AU - Venskutonytė, Raminta

AU - Mirza, Osman

AU - Gajhede, Michael

AU - Boesen, Thomas

AU - Kastrup, Jette Sandholm

N1 - Funding Information: We would like to thank Eric Gouaux for kindly providing the GluA2cryst construct, Heidi Peterson for help with GluA2cryst purification, Ole Kristensen for help using XIA2 and beamline scientists at ESRF, Grenoble, France; MAX‐lab, Lund, Sweden; BESSY, Berlin, Germany; SLS, Villigen, Switzerland; and Diamond, Oxford, UK, for their help during data collections. Funding is acknowledged from GluTarget, Danish Council for Independent Research—Medical Sciences, Lundbeck Foundation, Danscatt, and BioStructX. Publisher Copyright: © 2020 Federation of European Biochemical Societies Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/2

Y1 - 2021/2

N2 - Ionotropic glutamate receptors are ligand-gated ion channels governing neurotransmission in the central nervous system. Three major types of antagonists are known for the AMPA-type receptor GluA2: competitive, noncompetitive (i.e., negative allosteric modulators; NAMs) used for treatment of epilepsy, and uncompetitive antagonists. We here report a 4.65 Å resolution X-ray structure of GluA2, revealing that four molecules of the competitive antagonist ZK200775 and four molecules of the NAM GYKI53655 are capable of binding at the same time. Using negative stain electron microscopy, we show that GYKI53655 alone or ZK200775/GYKI53655 in combination predominantly results in compact receptor forms. The agonist AMPA provides a mixed population of compact and bulgy shapes of GluA2 not impacted by addition of GYKI53655. Taken together, this suggests that the two different mechanisms of antagonism that lead to channel closure are independent and that the distribution between bulgy and compact receptors primarily depends on the ligand bound in the glutamate binding site. Database: The atomic coordinates and structure factors from the crystal structure determination have been deposited in the Protein Data Bank under accession code https://doi.org/10.2210/pdb6RUQ/pdb. The electron microscopy 3D reconstruction volumes have been deposited in EMDB (EMD-4875: Apo; EMD-4920: ZK200775/GYKI53655; EMD-4921: AMPA compact; EMD-4922: AMPA/GYKI53655 bulgy; EMD-4923: GYKI53655; EMD-4924: AMPA bulgy; EMD-4925: AMPA/GYKI53655 compact).

AB - Ionotropic glutamate receptors are ligand-gated ion channels governing neurotransmission in the central nervous system. Three major types of antagonists are known for the AMPA-type receptor GluA2: competitive, noncompetitive (i.e., negative allosteric modulators; NAMs) used for treatment of epilepsy, and uncompetitive antagonists. We here report a 4.65 Å resolution X-ray structure of GluA2, revealing that four molecules of the competitive antagonist ZK200775 and four molecules of the NAM GYKI53655 are capable of binding at the same time. Using negative stain electron microscopy, we show that GYKI53655 alone or ZK200775/GYKI53655 in combination predominantly results in compact receptor forms. The agonist AMPA provides a mixed population of compact and bulgy shapes of GluA2 not impacted by addition of GYKI53655. Taken together, this suggests that the two different mechanisms of antagonism that lead to channel closure are independent and that the distribution between bulgy and compact receptors primarily depends on the ligand bound in the glutamate binding site. Database: The atomic coordinates and structure factors from the crystal structure determination have been deposited in the Protein Data Bank under accession code https://doi.org/10.2210/pdb6RUQ/pdb. The electron microscopy 3D reconstruction volumes have been deposited in EMDB (EMD-4875: Apo; EMD-4920: ZK200775/GYKI53655; EMD-4921: AMPA compact; EMD-4922: AMPA/GYKI53655 bulgy; EMD-4923: GYKI53655; EMD-4924: AMPA bulgy; EMD-4925: AMPA/GYKI53655 compact).

KW - agonist

KW - competitive antagonist

KW - electron microscopy.

KW - GluA2

KW - Ionotropic glutamate receptor

KW - negative allosteric modulator

KW - X-ray crystallography

UR - https://www.scopus.com/pages/publications/85087694502

U2 - 10.1111/febs.15455

DO - 10.1111/febs.15455

M3 - Journal article

C2 - 32543078

AN - SCOPUS:85087694502

SN - 1742-464X

VL - 288

SP - 995

EP - 1007

JO - FEBS journal

JF - FEBS journal

IS - 3

ER -