On-Cell Saturation Transfer Difference NMR Spectroscopy on Ion Channels: Characterizing Negative Allosteric Modulator...

Area of Science:

• Biochemistry
• Structural Biology
• Pharmacology

Background:

• P2X7 receptors are crucial drug targets for various diseases, including psychiatric disorders and cancer.
• Structural characterization of membrane-embedded P2X7 receptors is challenging, with limited available X-ray and cryo-EM structures.
• Existing structural data for P2X7 antagonists is scarce, hindering drug design efforts.

Purpose of the Study:

• To explore the utility of on-cell saturation transfer difference (STD) NMR for characterizing P2X7 receptor complexes.
• To determine the binding epitope mapping of P2X7 antagonists AZ10606120 and JNJ-47965567.
• To develop the first NMR-validated ligand binding models for P2X7 antagonists.

Main Methods:

• On-cell STD NMR was performed on mammalian cells overexpressing P2X7 receptors.
• Ligand binding epitope mapping was determined for P2X7 antagonists AZ10606120 and JNJ-47965567.
• Molecular docking was employed in conjunction with NMR data to build ligand binding models.

Main Results:

• On-cell STD NMR successfully provided structural insights into P2X7 receptor complexes with two negative allosteric modulators.
• The binding epitope mapping revealed key interaction regions between the ligands and the P2X7 binding pocket.
• The study presents the first NMR-validated models of antagonists bound to human P2X7 receptors, correlating structural data with pharmacology.

Conclusions:

• On-cell STD NMR is a powerful, less resource-intensive technique for studying membrane-embedded proteins like P2X7 receptors.
• This approach facilitates structure-activity relationship studies, aiding in the knowledge-based development of P2X7-targeting drugs.
• The methodology holds transformative potential for drug design targeting P2X7 and other ion channels or membrane proteins.