Protein–Ligand Interaction Modeling for Mechanistic & SAR Insights
Go beyond binding poses. Elucidate interaction fingerprints, quantify non-covalent forces, and derive structure–activity relationships with our specialized interaction modeling workflows.
Protein–Ligand Interaction Modeling Service Coverage
Interaction Fingerprinting
Generate binary or weighted interaction fingerprints for H-bonds, hydrophobic contacts, ionic interactions, and π-stacking. Enable rapid similarity searching, clustering, and diversity analysis across compound sets.
Per-Residue Energy Decomposition
Decompose binding free energy into residue-wise contributions (van der Waals, electrostatics, solvation). Identify hotspots and critical residues for potency and selectivity.
Water & Solvent Analysis
Map water molecules in the binding site, assess their thermodynamic profiles, and identify displaceable waters to guide rational lead optimization and affinity improvement.
Structure–Activity Relationship (SAR) Correlation
Map interaction patterns to experimental activity data. Uncover activity cliffs, identify key interaction motifs, and prioritize compounds for synthesis.
Selectivity & Cross-Reactivity Profiling
Compare interaction fingerprints and energy decompositions across related targets to guide selectivity design and minimize off-target effects.
MD-Based Interaction Analysis
Analyze interaction stability and dynamics from molecular dynamics trajectories, including contact occupancies, hydrogen bond lifetimes, and water residence times.
Core Calculation Methods
Interaction Fingerprint (IFP) Generation
Using PLIF, SIFt, or custom pharmacophore-based fingerprints to encode protein-ligand interactions into robust descriptors for chemoinformatics and machine learning.
MM-GBSA & MM-PBSA Decomposition
End-point free energy methods with residue-wise decomposition to quantify per-residue contributions and solvation effects.
WaterMap & Solvent Thermodynamics
Grid-based water analysis to compute enthalpic and entropic contributions of water molecules in the binding site.
Geometric Contact & Distance Analysis
Detailed analysis of interatomic distances, angles, and occupancies for all non-covalent interactions.
MD Trajectory Interaction Analysis
Extract interaction fingerprints, H-bond occupancies, and water residence times from molecular dynamics simulations.
2D & 3D Interaction Diagrams
Automated generation of publication-quality interaction diagrams with color-coded interaction types and residue labels.
Real Research Scenarios We Solve
Selectivity Optimization
Challenge: Lead compound shows off-target activity against a related kinase.
Solution: Cross-target interaction profiling identifies a unique hydrophobic pocket; guide design of selective analogs with 50x selectivity.
Hit-to-Lead Prioritization
Challenge: 50 hits from screening; limited capacity for synthesis.
Solution: IFP clustering + SAR correlation prioritizes 5 chemotypes with optimal interaction profiles and activity.
Binding Mode Validation
Challenge: Docking poses inconsistent with mutagenesis data.
Solution: Interaction fingerprinting and energy decomposition identify the most plausible binding mode consistent with experimental data.
Fragment Linking & Growing
Challenge: Two fragments bind in adjacent pockets; linking strategy unclear.
Solution: Interaction analysis identifies optimal vectors and linker geometries for fragment merging.
Residue Hotspot Mapping
Challenge: Identify which residues drive binding affinity for a series.
Solution: Per-residue energy decomposition across analogs pinpoints critical hotspots for optimization.
Selectivity Against Off-Targets
Challenge: Compound shows activity against a related family member.
Solution: Interaction fingerprint comparison reveals differences in a key subpocket, guiding selective design.
Why Work with CD ComputaBio for Interaction Modeling?
Our team combines deep expertise in computational chemistry with a focus on actionable insights. We don't just generate data – we interpret it in the context of your project goals, delivering clear recommendations for design and optimization.
Our Interaction Modeling Workflow
Structure & Ligand Preparation
Curate protein and ligand structures, assign protonation, tautomers, and optimize geometry.
Docking & Pose Generation
Generate high-quality binding poses using flexible docking protocols.
Interaction Fingerprinting & Scoring
Compute interaction fingerprints, energy decomposition, and solvent analysis.
SAR & Prioritization
Correlate interaction patterns with activity data to prioritize compounds and identify optimization vectors.
Interactive Visualization & Report
Deliver interactive 3D visualizations, 2D interaction diagrams, and a comprehensive technical report.
Inputs
- Protein structure (PDB, homology model, or AlphaFold)
- Ligand set (SDF, SMILES, or Mol2) – from a few to hundreds of compounds
- Binding site definition (or co-crystallized ligand)
- Activity data (optional, for SAR correlation)
- Specific questions: hotspot identification, selectivity, water analysis, etc.
Deliverables
- Interaction fingerprint (IFP) matrix and similarity analysis
- Per-residue energy decomposition plots and tables
- WaterMap / solvent analysis (if applicable)
- Detailed contact lists (H-bonds, hydrophobic, π-stacking, salt bridges)
- SAR correlation plots and prioritized compound lists
- Interactive 3D visualization files (PyMOL, Schrödinger)
- Comprehensive technical report with methods and interpretation
Recent Interaction Modeling Projects
IFP-based SAR analysis
Goal: rationalize activity cliffs.
Approach: docking + IFP clustering + activity mapping → identified key H-bond as activity switch.
Selectivity profiling
Goal: improve kinase selectivity.
Approach: per-residue decomposition across 5 kinases → designed selective analog with 50x selectivity.
Water displacement strategy
Goal: boost potency.
Approach: WaterMap + docking → replaced a water with a methyl group → 8x affinity gain.
Frequently Asked Questions
What is the difference between docking and interaction modeling?
Docking focuses on generating binding poses and ranking by affinity. Interaction modeling goes further: it quantifies and classifies the specific interactions (H-bonds, hydrophobic, etc.), decomposes energy, and correlates with SAR, providing deeper mechanistic insight.
Can you perform interaction modeling for covalent inhibitors?
Yes. We can analyze covalent adducts and include the covalent bond in interaction fingerprints and energy decomposition, offering a complete picture of binding.
Do I need activity data for interaction modeling?
Not necessarily. However, if you have activity data, we can perform SAR correlation analysis to map interaction patterns to potency, which is invaluable for lead optimization.
How long does an interaction modeling project take?
Typical projects range from 2–4 weeks depending on library size and complexity. Rapid turnaround is available for urgent projects.
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