docking

Docking — Protein-Ligand Docking & Virtual Screening

AutoDock Vina 1.2 · Gnina · pdbfixer · ProLIF · fpocket. For structure-based drug design: binding mode prediction, virtual screening, and lead optimization by docking.

When to Use This Skill

• Predicting how a small molecule binds to a protein (binding mode / pose)
• Virtual screening: ranking a library of compounds by predicted binding affinity
• Validating a pharmacophore hypothesis in 3D structural context
• Ensemble docking to account for protein flexibility
• Re-scoring docking poses with physics-based (MM-GB/SA) or CNN-based scoring
• Fragment-based screening (→ see fbdd skill for growing/linking)

Decision Tree — Docking vs. Other Methods

Input: protein structure 3D?
  NO  → ligand-based methods (pharmacophore, QSAR, similarity search)
  YES → docking

Compound set size?
  > 10 000   → VS pipeline (references/virtual-screening.md)
  10–10 000  → standard docking batch (references/vina-gnina.md)
  < 10       → manual docking + careful pose analysis

Goal: binding mode accuracy vs. ranking accuracy?
  Binding mode → high exhaustiveness, Gnina CNN rescoring
  Ranking      → standard Vina + clustering + MM-GB/SA rescore

Protein structure source?
  X-ray / CryoEM  → direct prep (references/protein-prep.md)
  Homology model  → validate first (→ homology-modeling skill)
  AlphaFold       → check pLDDT > 80 in pocket region before docking

Quick Start

import subprocess
from pathlib import Path

# 1. Prepare receptor (pdbfixer + obabel → PDBQT)
# See references/protein-prep.md for full workflow

# 2. Prepare ligand
import subprocess
subprocess.run([
    "obabel", "ligand.sdf", "-O", "ligand.pdbqt",
    "--gen3d", "-h"
], check=True)

# 3. Run Vina
result = subprocess.run([
    "vina",
    "--receptor", "receptor.pdbqt",
    "--ligand",   "ligand.pdbqt",
    "--center_x", "10.5",
    "--center_y", "-2.3",
    "--center_z", "14.1",
    "--size_x",   "20",
    "--size_y",   "20",
    "--size_z",   "20",
    "--exhaustiveness", "16",
    "--num_modes", "9",
    "--out", "docked.pdbqt"
], capture_output=True, text=True, check=True)

# 4. Parse best score
for line in result.stdout.splitlines():
    if line.strip().startswith("1 "):
        print("Best score:", line.split()[1], "kcal/mol")
        break