Pharmacophore modeling using site-identification by ligand competitive saturation (SILCS) with multiple probe...

Area of Science:

• Computational chemistry
• Drug discovery
• Structural biology

Background:

• Receptor-based pharmacophore modeling is crucial for computer-aided drug design.
• Existing methods often approximate protein flexibility and desolvation, limiting practical applications.
• The Site-Identification by Ligand Competitive Saturation (SILCS) approach addresses these limitations through molecular dynamics simulations.

Purpose of the Study:

• To extend and validate the SILCS-assisted pharmacophore modeling (SILCS-Pharm) protocol.
• To improve the accuracy and scope of pharmacophore modeling by incorporating a wider range of probe molecules.
• To enhance the identification and diversity of potential drug leads.

Main Methods:

• Extended the SILCS-Pharm protocol using diverse probe molecules (e.g., benzene, methanol, acetate) beyond water.
• Utilized full molecular dynamics simulations to generate 3D affinity maps, capturing protein flexibility and desolvation.
• Employed complementary features and volume constraints derived from SILCS exclusion maps.
• Implemented reranking using SILCS-based ligand grid free energies.

Main Results:

• The enhanced SILCS-Pharm protocol demonstrated improved screening results across multiple protein targets compared to the previous version.
• Validation against five additional protein targets showed superior screening performance over common docking methods.
• The inclusion of diverse probe types and features significantly improved the identification of potential drug candidates.
• Reranking enhanced the diversity of identified ligands for most targets.

Conclusions:

• The expanded SILCS-Pharm protocol offers a more robust and accurate approach to receptor-based pharmacophore modeling.
• Explicitly including protein flexibility and desolvation effects with diverse probes enhances lead identification.
• This refined protocol is a valuable tool for rational drug design and discovery.