Apo and InsP₃-bound crystal structures of the ligand-binding domain of an InsP₃ receptor

Nat Struct Mol Biol. 2011 Sep 4;18(10):1172-4. doi: 10.1038/nsmb.2112.


We report the crystal structures of the ligand-binding domain (LBD) of a rat inositol 1,4,5-trisphosphate receptor (InsP(3)R) in its apo and InsP(3)-bound conformations. Comparison of these two conformations reveals that LBD's first β-trefoil fold (β-TF1) and armadillo repeat fold (ARF) move together as a unit relative to its second β-trefoil fold (β-TF2). Whereas apo LBD may spontaneously transition between gating conformations, InsP(3) binding shifts this equilibrium toward the active state.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Crystallography, X-Ray
  • Inositol 1,4,5-Trisphosphate Receptors / chemistry
  • Inositol 1,4,5-Trisphosphate Receptors / metabolism*
  • Ligands
  • Models, Molecular
  • Protein Conformation
  • Rats


  • Inositol 1,4,5-Trisphosphate Receptors
  • Ligands

Associated data

  • PDB/3T8S