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

Research output: Contribution to journalArticle

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.

Details

Authors
  • Christian Krintel
  • Karla Frydenvang
  • Lars Olsen
  • Maria T Kristensen
  • Oriol de Barrios
  • Peter Naur
  • Pierre Francotte
  • Bernard Pirotte
  • Michael Gajhede
  • Jette S Kastrup
External organisations
  • University of Copenhagen
Original languageUnknown
Pages (from-to)173-178
JournalBiochemical Journal
Volume441
Issue number1
Publication statusPublished - 2012
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes

Related research output

Christian Krintel, Frydenvang, K., Olsen, L., Kristensen, M. T., de Barrios, O., Naur, P., Francotte, P., Pirotte, B. & Gajhede, M., 2011, p. P58.

Research output: Contribution to conferencePoster

View all (1)