Probing non-peptide agonists binding at the human nociceptin/orphanin FQ receptor: a molecular modelling study

Area of Science:

• Pharmacology
• Structural Biology
• Computational Chemistry

Background:

• The nociceptin/orphaninFQ (NOP) receptor is a key target for developing analgesics with fewer side effects than traditional opioids.
• Existing structural data for the NOP receptor includes complexes with its endogenous agonist and antagonists, but active-state agonist binding remains unclear.

Purpose of the Study:

• To develop and validate a computational protocol for predicting small molecule agonist binding modes at the NOP receptor active state.
• To provide insights into the binding mechanisms of selective small molecule agonists for NOP receptor drug development.

Main Methods:

• Utilized existing X-ray and cryo-EM structures of the NOP receptor.
• Employed a computational protocol combining molecular docking and short molecular dynamics (MD) simulations.
• Used N/OFQ(1-13)-NH2 as a reference compound for validation.

Main Results:

• The developed protocol successfully suggested reproducible and stable binding modes for small molecule agonists.
• Predicted binding modes are consistent with the active state of the solvated, membrane-embedded NOP receptor.
• Results align with established structure-activity relationship (SAR) data.

Conclusions:

• The computational protocol offers a reliable method for elucidating small molecule agonist binding at the NOP receptor.
• This approach can guide the design of novel NOP receptor-targeting analgesics.
• Further structural insights into NOP receptor active states are crucial for drug discovery.