Quantitative Prediction of Dissociation Rates of PYK2 Ligands Using Umbrella Sampling and Milestoning

Area of Science:

• Biophysics
• Computational Chemistry
• Structural Biology

Background:

• Protein kinases are crucial drug targets.
• Understanding ligand-protein interactions is key to drug design.
• PYK2 is implicated in various cellular processes.

Purpose of the Study:

• To investigate the dissociation mechanisms of multiple ligands from protein kinase PYK2.
• To correlate simulation-derived activation barriers with experimental dissociation rates.
• To elucidate the influence of ligand structure on dissociation pathways and protein dynamics.

Main Methods:

• Umbrella sampling simulations to calculate potential of mean force and activation barriers.
• Milestoning simulations to determine absolute dissociation rates.
• Zero-temperature string method to find optimized dissociation pathways.

Main Results:

• Activation barriers from umbrella sampling correlated well with experimental dissociation rates.
• Milestoning simulations accurately predicted dissociation rates for two of three similar ligands.
• Ligands followed distinct dissociation pathways, interacting with different residues.
• Protein PYK2 exhibited varied conformational changes during ligand dissociation.

Conclusions:

• Computational methods can effectively model ligand dissociation from protein kinases.
• Ligand structure significantly influences binding site exit pathways and protein conformational changes.
• Predicting dissociation rates for structurally similar ligands can be challenging due to complex exit routes.