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Thermodynamics and structural analysis of positive allosteric modulation of the ionotropic glutamate receptor GluA2

Krintel, Christian LU ; Frydenvang, Karla ; Olsen, Lars ; Kristensen, Maria T ; de Barrios, Oriol ; Naur, Peter ; Francotte, Pierre ; Pirotte, Bernard ; Gajhede, Michael and Kastrup, Jette S (2012) In Biochemical Journal 441(1). p.173-178
Abstract
Positive allosteric modulators of the ionotropic glutamate receptor-2 (GluA2) are promising compounds for the treatment of cognitive disorders, e.g. Alzheimer's disease. These modulators bind within the dimer interface of the LBD (ligand-binding domain) and stabilize the agonist-bound conformation slowing receptor desensitization and/or deactivation. In the present study, we employ isothermal titration calorimetry to determine binding affinities and thermodynamic details of binding of modulators of GluA2. A mutant of the LBD of GluA2 (LBD-L483Y-N754S) that forms a stable dimer in solution was used. The potent GluA2 modulator BPAM-97 was used as a reference compound. Evidence that BPAM-97 binds in the same pocket as the well-known GluA2... (More)
Positive allosteric modulators of the ionotropic glutamate receptor-2 (GluA2) are promising compounds for the treatment of cognitive disorders, e.g. Alzheimer's disease. These modulators bind within the dimer interface of the LBD (ligand-binding domain) and stabilize the agonist-bound conformation slowing receptor desensitization and/or deactivation. In the present study, we employ isothermal titration calorimetry to determine binding affinities and thermodynamic details of binding of modulators of GluA2. A mutant of the LBD of GluA2 (LBD-L483Y-N754S) that forms a stable dimer in solution was used. The potent GluA2 modulator BPAM-97 was used as a reference compound. Evidence that BPAM-97 binds in the same pocket as the well-known GluA2 modulator cyclothiazide was obtained from X-ray structures. The LBD-L483Y-N754S:BPAM-97 complex has a Kd of 5.6 μM (ΔH=-4.9 kcal/mol, -TΔS=-2.3 kcal/mol; where 1 kcal≈4.187 kJ). BPAM-97 was used in a displacement assay to determine a Kd of 0.46 mM (ΔH=-1.2 kcal/mol, -TΔS=-3.3 kcal/mol) for the LBD-L483Y-N754S:IDRA-21 complex. The major structural factors increasing the potency of BPAM-97 over IDRA-21 are the increased van der Waals contacts to, primarily, Met496 in GluA2 imposed by the ethyl substituent of BPAM-97. These results add important information on binding affinities and thermodynamic details, and provide a new tool in the development of drugs against cognitive disorders. (Less)
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author
; ; ; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
in
Biochemical Journal
volume
441
issue
1
pages
173 - 178
publisher
Portland Press
external identifiers
  • scopus:84055219498
ISSN
0264-6021
DOI
10.1042/BJ20111221
language
English
LU publication?
no
id
aa7928dd-476a-4b8f-bfef-80ce4547781c
date added to LUP
2017-06-10 06:51:34
date last changed
2022-06-21 14:25:38
@article{aa7928dd-476a-4b8f-bfef-80ce4547781c,
  abstract     = {{Positive allosteric modulators of the ionotropic glutamate receptor-2 (GluA2) are promising compounds for the treatment of cognitive disorders, e.g. Alzheimer's disease. These modulators bind within the dimer interface of the LBD (ligand-binding domain) and stabilize the agonist-bound conformation slowing receptor desensitization and/or deactivation. In the present study, we employ isothermal titration calorimetry to determine binding affinities and thermodynamic details of binding of modulators of GluA2. A mutant of the LBD of GluA2 (LBD-L483Y-N754S) that forms a stable dimer in solution was used. The potent GluA2 modulator BPAM-97 was used as a reference compound. Evidence that BPAM-97 binds in the same pocket as the well-known GluA2 modulator cyclothiazide was obtained from X-ray structures. The LBD-L483Y-N754S:BPAM-97 complex has a Kd of 5.6 μM (ΔH=-4.9 kcal/mol, -TΔS=-2.3 kcal/mol; where 1 kcal≈4.187 kJ). BPAM-97 was used in a displacement assay to determine a Kd of 0.46 mM (ΔH=-1.2 kcal/mol, -TΔS=-3.3 kcal/mol) for the LBD-L483Y-N754S:IDRA-21 complex. The major structural factors increasing the potency of BPAM-97 over IDRA-21 are the increased van der Waals contacts to, primarily, Met496 in GluA2 imposed by the ethyl substituent of BPAM-97. These results add important information on binding affinities and thermodynamic details, and provide a new tool in the development of drugs against cognitive disorders.}},
  author       = {{Krintel, Christian and Frydenvang, Karla and Olsen, Lars and Kristensen, Maria T and de Barrios, Oriol and Naur, Peter and Francotte, Pierre and Pirotte, Bernard and Gajhede, Michael and Kastrup, Jette S}},
  issn         = {{0264-6021}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{173--178}},
  publisher    = {{Portland Press}},
  series       = {{Biochemical Journal}},
  title        = {{Thermodynamics and structural analysis of positive allosteric modulation of the ionotropic glutamate receptor GluA2}},
  url          = {{http://dx.doi.org/10.1042/BJ20111221}},
  doi          = {{10.1042/BJ20111221}},
  volume       = {{441}},
  year         = {{2012}},
}