Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues

Mette B Hermit; Jeremy R Greenwood; Hans Bräuner-Osborne

doi:10.1074/jbc.M404109200

Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues

Mette B Hermit, Jeremy R Greenwood, Hans Bräuner-Osborne

15 Citations (Scopus)

Abstract

The metabotropic glutamate receptors (mGluRs) are key modulators of excitatory neurotransmission in the central nervous system. The eight mGluR subtypes are seven trans-membrane-spanning proteins that possess a large extracellular amino-terminal domain in which the endogenous ligand binding pocket resides. In this study, we have identified four non-conserved amino acid residues that are essential for differentiating mGluR1 from mGluR4. Our approach has been to increase the affinity of the classic mGluR1 agonists, quisqualic acid and ibotenic acid, at mGluR4 by making various point mutations that mimicked mGluR1 residues. Based on ligand docking to homology models, the non-conserved residues, Lys-74, Glu-287, Ser-313, and Lys-317, were chosen for the mutational studies and all of the mutations proved capable of partially or completely restoring the affinities of the ligands. In particular, the mutations K74Y and K317R induced dramatic triple-order-of-magnitude increases in the affinity of ibotenic acid at mGluR4, making the affinity equivalent to that of mGluR1. Furthermore, the affinity of quisqualic acid at mGluR4 was increased to the same level as mGluR1 by the two double mutations, K74Y/K317R and K74Y/E287G. Advanced analysis of ligand conformation and docking procedures were used for the interpretation of these results. The study shows that mGluR subtype selectivity results from a complex interplay of residues shaping the binding pocket, rather than being attributable to a single specific ligand-receptor interaction.

Original language	English
Journal	Journal of Biological Chemistry
Volume	279
Issue number	33
Pages (from-to)	34811-7
ISSN	0021-9258
DOIs	https://doi.org/10.1074/jbc.M404109200
Publication status	Published - 13 Aug 2004

Keywords

Cell Differentiation
Cell Line
Cloning, Molecular
Dose-Response Relationship, Drug
Excitatory Amino Acid Agonists
Glutamic Acid
Humans
Ibotenic Acid
Immunohistochemistry
Kinetics
Ligands
Lysine
Models, Chemical
Models, Genetic
Models, Molecular
Mutation
Point Mutation
Protein Binding
Protein Conformation
Quisqualic Acid
Receptors, Metabotropic Glutamate
Serine
Transfection

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Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues. / Hermit, Mette B; Greenwood, Jeremy R; Bräuner-Osborne, Hans.

In: Journal of Biological Chemistry, Vol. 279, No. 33, 13.08.2004, p. 34811-7.

Research output: Contribution to journal › Journal article › Research › peer-review

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title = "Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues",

abstract = "The metabotropic glutamate receptors (mGluRs) are key modulators of excitatory neurotransmission in the central nervous system. The eight mGluR subtypes are seven trans-membrane-spanning proteins that possess a large extracellular amino-terminal domain in which the endogenous ligand binding pocket resides. In this study, we have identified four non-conserved amino acid residues that are essential for differentiating mGluR1 from mGluR4. Our approach has been to increase the affinity of the classic mGluR1 agonists, quisqualic acid and ibotenic acid, at mGluR4 by making various point mutations that mimicked mGluR1 residues. Based on ligand docking to homology models, the non-conserved residues, Lys-74, Glu-287, Ser-313, and Lys-317, were chosen for the mutational studies and all of the mutations proved capable of partially or completely restoring the affinities of the ligands. In particular, the mutations K74Y and K317R induced dramatic triple-order-of-magnitude increases in the affinity of ibotenic acid at mGluR4, making the affinity equivalent to that of mGluR1. Furthermore, the affinity of quisqualic acid at mGluR4 was increased to the same level as mGluR1 by the two double mutations, K74Y/K317R and K74Y/E287G. Advanced analysis of ligand conformation and docking procedures were used for the interpretation of these results. The study shows that mGluR subtype selectivity results from a complex interplay of residues shaping the binding pocket, rather than being attributable to a single specific ligand-receptor interaction.",

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author = "Hermit, {Mette B} and Greenwood, {Jeremy R} and Hans Br{\"a}uner-Osborne",

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T1 - Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues

AU - Hermit, Mette B

AU - Greenwood, Jeremy R

AU - Bräuner-Osborne, Hans

PY - 2004/8/13

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N2 - The metabotropic glutamate receptors (mGluRs) are key modulators of excitatory neurotransmission in the central nervous system. The eight mGluR subtypes are seven trans-membrane-spanning proteins that possess a large extracellular amino-terminal domain in which the endogenous ligand binding pocket resides. In this study, we have identified four non-conserved amino acid residues that are essential for differentiating mGluR1 from mGluR4. Our approach has been to increase the affinity of the classic mGluR1 agonists, quisqualic acid and ibotenic acid, at mGluR4 by making various point mutations that mimicked mGluR1 residues. Based on ligand docking to homology models, the non-conserved residues, Lys-74, Glu-287, Ser-313, and Lys-317, were chosen for the mutational studies and all of the mutations proved capable of partially or completely restoring the affinities of the ligands. In particular, the mutations K74Y and K317R induced dramatic triple-order-of-magnitude increases in the affinity of ibotenic acid at mGluR4, making the affinity equivalent to that of mGluR1. Furthermore, the affinity of quisqualic acid at mGluR4 was increased to the same level as mGluR1 by the two double mutations, K74Y/K317R and K74Y/E287G. Advanced analysis of ligand conformation and docking procedures were used for the interpretation of these results. The study shows that mGluR subtype selectivity results from a complex interplay of residues shaping the binding pocket, rather than being attributable to a single specific ligand-receptor interaction.

AB - The metabotropic glutamate receptors (mGluRs) are key modulators of excitatory neurotransmission in the central nervous system. The eight mGluR subtypes are seven trans-membrane-spanning proteins that possess a large extracellular amino-terminal domain in which the endogenous ligand binding pocket resides. In this study, we have identified four non-conserved amino acid residues that are essential for differentiating mGluR1 from mGluR4. Our approach has been to increase the affinity of the classic mGluR1 agonists, quisqualic acid and ibotenic acid, at mGluR4 by making various point mutations that mimicked mGluR1 residues. Based on ligand docking to homology models, the non-conserved residues, Lys-74, Glu-287, Ser-313, and Lys-317, were chosen for the mutational studies and all of the mutations proved capable of partially or completely restoring the affinities of the ligands. In particular, the mutations K74Y and K317R induced dramatic triple-order-of-magnitude increases in the affinity of ibotenic acid at mGluR4, making the affinity equivalent to that of mGluR1. Furthermore, the affinity of quisqualic acid at mGluR4 was increased to the same level as mGluR1 by the two double mutations, K74Y/K317R and K74Y/E287G. Advanced analysis of ligand conformation and docking procedures were used for the interpretation of these results. The study shows that mGluR subtype selectivity results from a complex interplay of residues shaping the binding pocket, rather than being attributable to a single specific ligand-receptor interaction.

KW - Cell Differentiation

KW - Cell Line

KW - Cloning, Molecular

KW - Dose-Response Relationship, Drug

KW - Excitatory Amino Acid Agonists

KW - Glutamic Acid

KW - Humans

KW - Ibotenic Acid

KW - Immunohistochemistry

KW - Kinetics

KW - Ligands

KW - Lysine

KW - Models, Chemical

KW - Models, Genetic

KW - Models, Molecular

KW - Mutation

KW - Point Mutation

KW - Protein Binding

KW - Protein Conformation

KW - Quisqualic Acid

KW - Receptors, Metabotropic Glutamate

KW - Serine

KW - Transfection

U2 - 10.1074/jbc.M404109200

DO - 10.1074/jbc.M404109200

M3 - Journal article

C2 - 15184361

SN - 0021-9258

VL - 279

SP - 34811

EP - 34817

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 33

ER -

Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues

Abstract

Keywords

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