Binding Kinetics Toolkit for Analyzing Transient Molecular Conformations and Computing Free Energy Landscapes

Area of Science:

• Computational Chemistry
• Biophysics
• Molecular Dynamics

Background:

• Understanding ligand binding kinetics and thermodynamics is crucial for chemical and biomedical applications.
• Transient ligand-protein conformations influence drug efficacy and selectivity.
• Mapping the free energy landscape of ligand binding is key to understanding molecular recognition.

Purpose of the Study:

• To present the Binding Kinetics Toolkit (BKiT) for analyzing molecular dynamics trajectories.
• To compute free energy and kinetics profiles for ligand binding/unbinding processes.
• To provide a comprehensive tool for understanding molecular recognition and guiding drug design.

Main Methods:

• Utilizing principal component space to generate unbinding or conformational transition coordinates.
• Implementing a partitioning approach for milestone/microstate assignment along coordinates.
• Employing milestoning theory with short molecular dynamics simulations to construct free energy profiles and estimate binding residence time.

Main Results:

• Validated the BKiT method with a host-guest system (aspirin/β-cyclodextrin).
• Applied the protocol to pyrazolourea compounds and cyclin-dependent kinase 8/cyclin C complexes.
• Achieved good agreement with published results and identified potential ligand design strategies.

Conclusions:

• BKiT provides a complete picture of the ligand-receptor binding free energy landscape.
• The toolkit aids in understanding binding barriers and stable local minima.
• BKiT is user-friendly with extensible features for future molecular dynamics post-analysis.