Peptide Virtual Screening Pipeline for Drug Discovery and Antigen Design
Peptide Virtual Screening Pipeline
Abstract
We present a computational protocol for virtual screening of peptide candidates against target proteins, combining AlphaFold 3 structure prediction with binding interface analysis. The pipeline enables rapid prioritization of peptide libraries for experimental validation by scoring binding likelihood based on interface confidence metrics.
Motivation
Peptide-protein interactions mediate critical biological processes including signal transduction, immune recognition, and enzyme regulation. Traditional experimental screening is resource-intensive. Computational pre-screening can dramatically reduce the experimental burden.
Methodology
Pipeline Overview
- Input Preparation: Target protein + peptide library
- Complex Prediction: AlphaFold 3 for each peptide-target pair
- Metric Extraction: Interface pLDDT, inter-chain PAE, contact count
- Composite Scoring: Weighted combination of metrics
- Ranking: Sorted candidate list with confidence categories
Scoring System
| Metric | Weight | Rationale |
|---|---|---|
| Interface pLDDT | 35% | Direct measure of confidence at interface |
| Inter-chain PAE | 25% | Positional accuracy between chains |
| Contact count | 20% | Physical interaction extent |
| Length suitability | 20% | Typical peptide length optimal (8-20 aa) |
Confidence Categories
- High (score >= 75): Strong computational evidence for binding
- Medium (55 <= score < 75): Moderate evidence, validation recommended
- Low (score < 55): Weak or no predicted binding
Expected Outcomes
For a screen of 100 peptide candidates:
- High confidence: 10-20 (10-20%)
- Medium confidence: 30-40 (30-40%)
- Low confidence: 40-60 (40-60%)
Limitations
- AlphaFold 3 predictions are computational hypotheses, not experimental evidence
- Does not account for PTMs, cellular concentrations, or allosteric effects
- Membrane proteins and disordered regions remain challenging
References
- CAMP: Ternavor et al., Nature Communications, 2021
- PepCNN: Peterson et al., Scientific Reports, 2023
- AlphaFold 3: Abramson et al., Nature, 2024
Reproducibility: Skill File
Use this skill file to reproduce the research with an AI agent.
--- name: peptide-virtual-screen-protocol description: Virtual screening pipeline for peptide-protein binding prediction using AlphaFold 3 structure prediction and binding affinity scoring. allowed-tools: WebFetch, Bash(python *), Bash(mkdir *), Bash(cp *), Bash(ls *), Bash(jq *), Bash(cd *) --- # Peptide Virtual Screening Pipeline ## Purpose Screen candidate peptide sequences for binding to a target protein by predicting peptide-protein complex structures and scoring binding likelihood. ## Inputs - `inputs/target.json`: Target protein in AlphaFold 3 JSON format - `inputs/peptides.fasta`: Candidate peptide sequences (5-30 aa) - `inputs/screen_config.yaml`: Configuration parameters ## Pre-Run Checks 1. Verify peptide sequences contain only standard amino acids 2. Check peptide lengths within supported range 3. Validate target JSON format ## Step 1: Parse Input Data Parse target JSON and peptide FASTA, create manifest. ## Step 2: Predict Complexes For each peptide, predict complex structure with AlphaFold 3. ## Step 3: Extract Binding Metrics Extract interface pLDDT, inter-chain PAE, contact count. ## Step 4: Calculate Binding Scores Composite = 0.35*pLDDT + 0.25*(100-pae*5) + 0.20*contacts + 0.20*length ## Step 5: Generate Report Rank peptides and generate prioritized validation list. ## Success Criteria - All peptides processed without crash - Metrics consistently extracted - Clear priority list produced ## Failure Modes - Invalid amino acids → skip and log - Prediction timeout → retry once - No interface → mark as non-binder
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