Interaction partners of PSD-93 studied by X-ray crystallography and fluorescence polarization spectroscopy

The structure of PSD-93 PDZ1 with a C-terminal GTSI extension to mimic the C-terminal tail of GluD2 shows flexibility in the binding cavity, resulting in variations in GTSI binding. Combined with the very low binding affinity of a GluD2 C-terminally derived peptide to PSD-93 PDZ1, PDZ2 and PDZ1-2, it raises doubts about the role of PSD-93 as a direct intracellular GluD2 receptor interaction partner.

Structural analysis of the positive AMPA receptor modulators CX516 and Me-CX516 in complex with the GluA2 ligand-binding domain

The crystal structures of the GluA2 ligand-binding domain in complex with the positive allosteric modulator CX516 and its methyl-substituted analogue Me-CX516 show that their binding modes are similar to those of aniracetam and CX614. This supports that CX516 affects receptor deactivation. The structures also show that there is limited space for substitutions at the piperidine ring of CX516.