Experimental and computational active site mapping as a starting point to fragment-based lead discovery

Area of Science:

• Structural biology
• Biochemistry
• Computational chemistry

Background:

• Understanding protein-ligand interactions is crucial for drug discovery.
• Fragment-based lead discovery relies on small molecules accurately representing binding site interactions.

Purpose of the Study:

• To map protein binding pockets and identify binding hot spots using small, soluble probe molecules.
• To validate the computational prediction of binding sites using experimental data.
• To confirm the utility of small probes in fragment-based drug design.

Main Methods:

• Soaking small probe molecules (e.g., aniline, urea, phenol) into protein crystals (thermolysin, kinase A, etc.).
• Determining crystal structures to observe probe molecule binding positions.
• Utilizing HotspotsX software for computational active site mapping and comparison with experimental data.

Main Results:

• Small probe molecules were observed to bind in an ordered fashion within protein binding pockets.
• Experimental binding hot spots showed good agreement with computational predictions.
• Observed poses of small probes closely matched those of larger, structurally related ligands.

Conclusions:

• Small molecule probes effectively map protein binding sites and identify key interaction points (hot spots).
• Computational methods like HotspotsX can accurately predict these binding sites.
• The study validates the fragment-based lead discovery approach, showing small probes serve as reliable starting points for drug design.