Overview
Use molecular docking to:- Screen large compound libraries
- Identify binding modes and key interactions
- Rank compounds by predicted affinity
- Optimize lead compounds
- Predict selectivity across protein families
Docking Methods
Rigid Docking
Fast screening for large libraries. Protein treated as rigid.
Flexible Docking
Accounts for protein and ligand flexibility. More accurate but slower.
Ensemble Docking
Dock against multiple protein conformations. Best for flexible targets.
Covalent Docking
Model covalent bond formation between ligand and protein.
Quick Start: Docking a Single Compound
Define Binding Site
Choose one of three methods:
- Auto-detect: Let Rosalind find binding pockets
- Residue selection: Specify key binding residues
- Grid box: Define xyz coordinates and box size
Select Scoring Function
- AutoDock Vina: Fast, generally reliable
- Gnina: ML-based, more accurate for some targets
- Consensus: Combines multiple scoring functions
Virtual Screening
Screen thousands to millions of compounds in parallel.Compound Libraries
LiteFold provides access to:- FDA-approved drugs (~3,000 compounds)
- Enamine REAL (>20 billion compounds)
- ZINC15 (>1 billion compounds)
- ChEMBL (>2 million bioactive compounds)
- Custom libraries: Upload your own
Screening Workflow
Apply Filters
Filter by molecular properties:
- Molecular weight
- LogP
- TPSA
- Rotatable bonds
- Drug-likeness (Lipinski, Veber)
Configure Docking
- Binding site definition
- Scoring function
- Number of poses per compound
- Energy cutoffs
Understanding Docking Results
Scoring and Ranking
Docking scores approximate binding affinity. Lower (more negative) is better. Typical score ranges:- < -10 kcal/mol: Strong binder
- -8 to -10: Moderate binder
- -6 to -8: Weak binder
- > -6: Likely non-binder
Binding Pose Analysis
For each compound, examine:- Orientation: How ligand sits in pocket
- Hydrogen bonds: Key polar interactions
- Hydrophobic contacts: Non-polar interactions
- π-π stacking: Aromatic interactions
- Salt bridges: Charged interactions
Interaction Maps
LiteFold automatically generates 2D interaction diagrams showing:- Residues within 4Å of ligand
- Hydrogen bond donors/acceptors
- Hydrophobic contacts
- Metal coordination
- π interactions
Advanced Features
Ensemble Docking
Dock against multiple protein conformations:- Generate ensemble from MD simulation or prediction
- Select representative conformations (5-10 typical)
- LiteFold docks ligand to all conformations
- Reports best pose and average score
- Captures induced fit effects
- More accurate for flexible proteins
- Reduces false negatives
Covalent Docking
Model covalent inhibitors:- Specify reactive residue (e.g., Cys797 in EGFR)
- Define warhead chemistry (e.g., acrylamide, chloroacetamide)
- LiteFold models covalent bond formation
- Scores combine non-covalent and covalent contributions
Water-Mediated Interactions
Include explicit water molecules:- Identify conserved waters in binding site
- Include during docking
- Capture water-mediated hydrogen bonds
Cofactor Handling
Automatically handles:- Metal ions (Mg²⁺, Zn²⁺, Ca²⁺)
- Cofactors (ATP, NAD, heme)
- Post-translational modifications
Customization Options
Receptor Preparation
- Protonation state: Auto or manual pH settings
- Tautomers: Consider alternative forms
- Flexible residues: Select sidechains to move
- Water removal: Keep/remove crystallographic waters
Ligand Preparation
- Conformer generation: Number of starting conformers
- Ionization: Set pH for protonation
- Tautomers: Generate tautomeric forms
- Stereoisomers: Expand undefined stereocenters
Docking Grid
- Center: xyz coordinates or residue-based
- Size: Box dimensions (Å)
- Resolution: Grid spacing (0.3-0.5 Å typical)
- Padding: Extra space around ligand
Best Practices
Scaffold Hopping
Find chemically distinct scaffolds with similar binding:- Dock your reference compound
- Click “Find alternative scaffolds”
- LiteFold searches for:
- Different core structures
- Similar binding mode
- Comparable predicted affinity
- Presents diverse hits for expansion
Selectivity Profiling
Dock compounds against multiple protein targets:- Assess selectivity vs. off-targets
- Identify promiscuous binders
- Predict side effects
- Optimize for selectivity
ADMET Prediction
For top docking hits, predict ADMET properties:- Absorption: Caco-2, MDCK permeability
- Distribution: Plasma protein binding, Vd
- Metabolism: CYP inhibition, metabolic stability
- Excretion: Clearance routes
- Toxicity: hERG, AMES, hepatotoxicity
Example: Virtual Screening Campaign
Let’s screen 100,000 compounds against EGFR kinase:Prepare Protein
- Use AlphaFold prediction or PDB 1M17
- Define ATP binding site
- Keep key water molecule (HOH 1077)
Run Screening
- AutoDock Vina scoring
- 10 poses per compound
- Parallel processing: completes in 4 hours
Analyze Results
- 842 compounds score < -8 kcal/mol
- Cluster into 23 chemical series
- Visual inspection of top 100
- 47 compounds selected for synthesis
Integration with Other Tools
Docking results flow to:- Molecular Dynamics: Validate binding with MD
- De Novo Design: Use binding mode as template
- SAR Analysis: Guide medicinal chemistry
- Rosalind AI: Ask “Why does compound A bind better?”
Next Steps
Molecular Dynamics
Validate docking with MD simulations
De Novo Design
Design novel molecules based on docking insights
Binding Affinity
Calculate precise binding free energies
Compound Screening
Complete virtual screening workflows