4H11: Interaction partners of PSD-93 studied by X-ray crystallography and fluorescent polarization spectroscopy

Citation:
Abstract
PSD-93 (chapsyn-110, DLG2) is a member of the family of membrane-associated guanylate kinase (MAGUK) proteins. The MAGUK proteins are involved in receptor localization and signalling pathways. The best characterized MAGUK protein, PSD-95, is known to be involved in NMDA receptor signalling via its PDZ domains. The PDZ domains of PSD-95 and PSD-93 are structurally very similar, but relatively little is known about the function of PSD-93. PSD-93 has been suggested to interact with GluD2 from the family of ionotropic glutamate receptors. Here, the interactions of four residues (GTSI) representing the extreme C-terminus of GluD2 with PSD-93 PDZ1 have been investigated in the crystalline phase. Two different binding modes of these residues were observed, suggesting that the peptide is not tightly bound to PSD-93 PDZ1. In accordance, the two N-terminal PSD-93 PDZ domains show no appreciable binding affinity for a GluD2-derived C-terminal octapeptide, whereas micromolar affinity was observed for a GluN2B-derived C-terminal octapeptide. This indicates that if present, the interactions between GluD2 and PSD-93 involve more than the extreme terminus of the receptor. In contrast, the tumour-suppressor protein SCRIB PDZ3 shows low micromolar affinity towards the GluD2-derived octapeptide, which is in agreement with previous findings using high-throughput assays.
PDB ID: 4H11Download
MMDB ID: 108852
PDB Deposition Date: 2012/9/10
Updated in MMDB: 2018/06
Experimental Method:
x-ray diffraction
Resolution: 1.67  Å
Source Organism:
Similar Structures:
Biological Unit for 4H11: monomeric; determined by author
Molecular Components in 4H11
Label Count Molecule
Protein (1 molecule)
1
Disks Large Homolog 2(Gene symbol: Dlg2)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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