3GBB

X-ray strucutre of iGluR5 ligand-binding core (S1S2) in complex with MSVIII-19 at 2.10A resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.201 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Full Domain Closure of the Ligand-binding Core of the Ionotropic Glutamate Receptor iGluR5 Induced by the High Affinity Agonist Dysiherbaine and the Functional Antagonist 8,9-Dideoxyneodysiherbaine

Frydenvang, K.Lash, L.L.Naur, P.Postila, P.A.Pickering, D.S.Smith, C.M.Gajhede, M.Sasaki, M.Sakai, R.Pentikainen, O.T.Swanson, G.T.Kastrup, J.S.

(2009) J.Biol.Chem. 284: 14219-14229

  • DOI: 10.1074/jbc.M808547200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The prevailing structural model for ligand activation of ionotropic glutamate receptors posits that agonist efficacy arises from the stability and magnitude of induced domain closure in the ligand-binding core structure. Here we describe an exception ...

    The prevailing structural model for ligand activation of ionotropic glutamate receptors posits that agonist efficacy arises from the stability and magnitude of induced domain closure in the ligand-binding core structure. Here we describe an exception to the correlation between ligand efficacy and domain closure. A weakly efficacious partial agonist of very low potency for homomeric iGluR5 kainate receptors, 8,9-dideoxyneodysiherbaine (MSVIII-19), induced a fully closed iGluR5 ligand-binding core. The degree of relative domain closure, approximately 30 degrees , was similar to that we resolved with the structurally related high affinity agonist dysiherbaine and to that of l-glutamate. The pharmacological activity of MSVIII-19 was confirmed in patch clamp recordings from transfected HEK293 cells, where MSVIII-19 predominantly inhibits iGluR5-2a, with little activation apparent at a high concentration (1 mm) of MSVIII-19 (<1% of mean glutamate-evoked currents). To determine the efficacy of the ligand quantitatively, we constructed concentration-response relationships for MSVIII-19 following potentiation of steady-state currents with concanavalin A (EC(50) = 3.6 microm) and on the nondesensitizing receptor mutant iGluR5-2b(Y506C/L768C) (EC(50) = 8.1 microm). MSVIII-19 exhibited a maximum of 16% of full agonist efficacy, as measured in parallel recordings with glutamate. Molecular dynamics simulations and electrophysiological recordings confirm that the specificity of MSVIII-19 for iGluR5 is partly attributable to interdomain hydrogen bond residues Glu(441) and Ser(721) in the iGluR5-S1S2 structure. The weaker interactions of MSVIII-19 with iGluR5 compared with dysiherbaine, together with altered stability of the interdomain interaction, may be responsible for the apparent uncoupling of domain closure and channel opening in this kainate receptor subunit.


    Related Citations: 
    • Crystal structure of the kainate receptor GluR5 ligand-binding core in complex with (S)-glutamate.
      Naur, P.,Vestergaard, B.,Skov, L.K.,Egebjerg, J.,Gajhede, M.,Kastrup, J.S.
      (2005) Febs Lett. 579: 1154


    Organizational Affiliation

    Department of Medicinal Chemistry and Pharmacology and Pharmacotherapy, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Glutamate receptor, ionotropic kainate 1
A, B
257Rattus norvegicusMutation(s): 0 
Gene Names: Grik1 (Glur5)
Find proteins for P22756 (Rattus norvegicus)
Go to UniProtKB:  P22756
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MS8
Query on MS8

Download SDF File 
Download CCD File 
A, B
(2R,3aR,7aR)-2-[(2S)-2-amino-3-hydroxy-3-oxo-propyl]-3,3a,5,6,7,7a-hexahydrofuro[4,5-b]pyran-2-carboxylic acid
C11 H17 N O6
RZIYCCQNKHONBB-PRKAOEEVSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
MS8Ki: 126 nM BINDINGMOAD
MS8Ki: 126 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.201 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 44.900α = 100.89
b = 45.120β = 92.31
c = 66.980γ = 94.65
Software Package:
Software NamePurpose
CNSrefinement
SCALAdata scaling
PDB_EXTRACTdata extraction
xia2data reduction
PHASERphasing
MAR345dtbdata collection
xia2data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-03-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2017-08-16
    Type: Data collection, Refinement description, Source and taxonomy
  • Version 1.3: 2017-11-01
    Type: Refinement description