Decoding Prolonged Residence Time of 5-HT_2A Receptor Antagonists: Insights from Ritanserin Derivatives.

Area of Science:

• Pharmacology and Drug Design
• Computational Chemistry
• Molecular Biology

Background:

• Ligand residence time (RT) influences compound activity and drug efficacy.
• RT is often neglected in early drug design due to focus on other factors.
• Molecular determinants of prolonged ligand binding are not fully understood.

Purpose of the Study:

• Investigate the molecular basis of prolonged ligand binding to the 5-HT2A receptor.
• Synthesize ritanserin derivatives with varied RT and determine their binding characteristics.
• Identify key receptor-ligand interactions contributing to long ligand occupancy.

Main Methods:

• In vitro synthesis and RT determination of ritanserin derivatives.
• Molecular modeling: docking and molecular dynamics simulations.
• Enhanced sampling techniques (metadynamics, RAMD) on native and mutant receptors.

Main Results:

• Identified specific receptor-ligand contacts associated with prolonged RT.
• Stable, geometrically optimized π-π interactions with Trp336 and Phe340 were highlighted.
• Demonstrated the role of these interactions in long ligand occupancy at 5-HT2A receptors.

Conclusions:

• Prolonged RT is linked to specific, stable molecular interactions at the 5-HT2A receptor.
• Provides novel hypotheses for designing 5-HT2A receptor ligands with extended duration of action.
• This comprehensive study offers a foundation for future drug development targeting sustained pharmacological effects.