Emerging the Role of the Structure of Brain Membrane Targets Recognizing Glutamate

Julianna      Kardos; Agnes      Simon; Akos      Bencsura; Anna      Pallo; Laszlo      Heja

Abstract

Ligand-bound and free structures of brain membrane targets for L-glutamate (Glu) suggest the view, that quaternary rearrangements are associated with ligand binding. Rearrangement of the machinery of the signaling apparatus, such as molecular switches, recognition sites and the target structures for ligand binding of Glu-operated ion channel and heptahelical G-protein-coupled family receptors have been quantified and compared with the use of the root mean square (RMS) values. In addition to conformational rearrangement of the Glu receptor structures in complex with a series of ligands, conformations of Glu in various target structures became available. High resolution data revealed that the extended Glu conformation is conserved in the binding crevice of all ionotropic Glu receptors (iGluRs). Furthermore, the extended conformations of Glu that characterize iGluRs and mGluRs are distinguishable by distance and torsion angle parameters, such as δC1-C2 and Cα-Cβ-Cγ-C2. By contrast, a bent Glu conformation is recognized in Glu transporters.

Keywords: PDB database analysis, ionotropic glutamate receptor, metabotropic glutamate receptor, glutamate transporter, glutamate conformation