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FDS: flexible ligand and receptor docking with a continuum solvent model and soft-core energy function
Richard D Taylor1, Philip J Jewsbury, Jonathan W Essex
1Department of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
Journal of Computational Chemistry
|August 20, 2003
Summary
This study introduces a two-stage simulation method for flexible ligand-protein docking. Including protein flexibility reveals multiple, energetically similar binding modes, suggesting a rugged energy landscape in molecular docking.
Area of Science:
- Computational chemistry
- Structural biology
- Drug discovery
Background:
- Accurate prediction of ligand-protein interactions is crucial for drug design.
- Flexible docking remains a challenge due to the conformational complexity of both ligands and proteins.
Purpose of the Study:
- To develop and validate a two-stage simulation-based method for flexible small molecule ligand docking to large protein targets.
- To investigate the impact of protein side-chain flexibility on the docking energy landscape and the identification of binding modes.
Main Methods:
- A hybrid approach combining graph theory, distance geometry, and cluster analysis for initial ligand-protein docking.
- Utilized a modified Monte Carlo algorithm with the AMBER-AA force field and Generalized Born/Surface Area (GB/SA) solvent model for energy minimization and sampling.
- Incorporated rotamer libraries and dihedral moves to enhance sampling of protein side-chain flexibility.
Main Results:
- For a rigid receptor model, the method accurately reproduced and uniquely identified the experimental binding geometry.
- Including protein side-chain flexibility resulted in multiple, energetically indistinguishable binding conformations, indicating a rugged docking energy hypersurface.
- The method successfully identified experimental binding modes in 13 out of 15 cases for rigid proteins and 11 out of 15 for flexible proteins, often within clusters of low-energy structures.
Conclusions:
- Protein flexibility significantly alters the docking energy landscape, making unique identification of the binding mode challenging.
- The findings suggest that multiple binding conformations may exist and should be considered during ligand optimization in drug discovery.
- The developed two-stage simulation method offers a valuable tool for exploring ligand-protein interactions, particularly when receptor flexibility is a factor.