Agent skill
binder-design
Guidance for choosing the right protein binder design tool. Use this skill when: (1) Deciding between BoltzGen, BindCraft, or RFdiffusion, (2) Planning a binder design campaign, (3) Understanding trade-offs between different approaches, (4) Selecting tools for specific target types. For specific tool parameters, use the individual tool skills (boltzgen, bindcraft, rfdiffusion, etc.).
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/data/binder-design
SKILL.md
Binder Design Tool Selection
Decision tree
De novo binder design?
│
├─ Standard target → BoltzGen (recommended)
│ All-atom output (no separate ProteinMPNN step needed)
│ Better for ligand/small molecule binding
│ Single-step design (backbone + sequence + side chains)
│
├─ Need diversity/exploration → RFdiffusion + ProteinMPNN
│ Maximum backbone diversity
│ Two-step: backbone then sequence
│
├─ Integrated validation → BindCraft
│ Built-in AF2 validation
│ End-to-end pipeline
│
├─ Ligand binding → BoltzGen ✓
│ All-atom diffusion handles ligand context
│
├─ Peptide/nanobody → Germinal
│ VHH/nanobody design
│ Germline-aware optimization
│
└─ Antibody/Nanobody
+-- VHH design --> germinal skill
Tool comparison
| Tool | Strengths | Weaknesses | Best For |
|---|---|---|---|
| BoltzGen | All-atom, single-step, ligand-aware | Higher GPU requirement | Standard (recommended) |
| BindCraft | End-to-end, built-in AF2 validation | Less diverse | Production campaigns |
| RFdiffusion | High diversity, fast | Requires ProteinMPNN | Exploration, diversity |
| Germinal | Nanobody/VHH design | Specialized | Antibody optimization |
Recommended Pipeline: BoltzGen → Chai → QC
BoltzGen provides all-atom design with built-in side-chain packing:
Target → BoltzGen → Validate → Filter
(pdb) (all-atom) (chai) (qc)
1. Target preparation
# Fetch structure from PDB
# Use pdb skill for guidance
- Trim to binding region + 10A buffer
- Remove waters and ligands
- Renumber chains if needed
2. Hotspot selection
- Choose 3-6 exposed residues
- Prefer charged/aromatic residues
- Cluster spatially (within 10-15A)
3. Design with BoltzGen (Recommended)
First, create a YAML config file (e.g., binder.yaml):
entities:
- protein:
id: B
sequence: 70..100
- file:
path: target.cif
include:
- chain:
id: A
binding_types:
- chain:
id: A
binding: 45,67,89
Then run:
modal run modal_boltzgen.py \
--input-yaml binder.yaml \
--protocol protein-anything \
--num-designs 50
Why BoltzGen?
- All-atom output (no separate ProteinMPNN step needed)
- Better for ligand/small molecule binding
- Single-step design (backbone + sequence + side chains)
4. Alternative: RFdiffusion Pipeline
For maximum diversity or when backbone-only is preferred:
# Step 1: Backbone generation
modal run modal_rfdiffusion.py \
--pdb target.pdb \
--contigs "A1-150/0 70-100" \
--hotspot "A45,A67,A89" \
--num-designs 500
# Step 2: Sequence design
modal run modal_ligandmpnn.py \
--pdb-path backbone.pdb \
--num-seq-per-target 16 \
--sampling-temp 0.1
5. Validation
modal run modal_chai1.py \
--input-faa sequences.fasta \
--out-dir predictions/
6. Filtering
Apply standard thresholds:
- pLDDT > 0.80
- ipTM > 0.50
- PAE_interface < 10
- scRMSD < 2.0 A
See protein-qc skill for details.
Number of designs
| Stage | Count | Purpose |
|---|---|---|
| Backbone generation | 500-1000 | Diversity |
| Sequences per backbone | 8-16 | Sequence space |
| AF2 predictions | All | Validation |
| After filtering | 50-200 | Candidates |
| Experimental testing | 10-50 | Final selection |
Common mistakes
Wrong hotspots
- Using buried residues
- Too many hotspots (over-constrain)
- Wrong chain/residue numbers
Insufficient diversity
- Too few designs generated
- Low temperature in ProteinMPNN
- Not exploring multiple backbones
Poor target preparation
- Including full protein instead of binding region
- Missing important structural features
- Wrong protonation states
Timeline guide
| Step | Compute Time |
|---|---|
| RFdiffusion (500 designs) | 2-4 hours |
| ProteinMPNN (8000 sequences) | 1-2 hours |
| AF2 prediction (8000 sequences) | 12-24 hours |
| Filtering and analysis | 1-2 hours |
Total: 1-2 days of compute
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