Bio Structure Annotation

Structure prediction and structure-based annotation.

Instructions

1. Run a fast embedding screen with TM-Vec to triage candidate proteins by remote homology before incurring structure-prediction cost.
2. Predict structures on a GPU node. AlphaFold3 is intentionally not part of this stack (non-commercial license, large VRAM footprint, no clear quality gap for the workflows in this repo). Use:

• Boltz-2 (MIT license; CUDA; NVIDIA cuEquivariance kernels) as the default predictor — joint structure-and-affinity, ~1000× faster than FEP for binding-affinity estimation, comparable accuracy to AF3 on benchmarked complexes.
• ColabFold v1.5.5+ with an MMseqs2-GPU MSA backend when a wider MSA than Boltz-2 builds is required (≈31.8× faster MSA generation versus the standard AF2 pipeline; Nature Protocols 2025, DOI: 10.1038/s41596-024-01060-5).
• ESMFold for fast monomer pre-screening only (15–20 GB VRAM; lower accuracy than Boltz-2).

1. Search predicted or experimental structures with Foldseek v9+. Use --gpu 1 on CUDA Turing or newer for the ProstT5-backed search (4–27× speedup). Consider Foldseek-Multimer when complex-vs-complex search is needed.
2. Annotate hits and route high-value unknowns back to /bio-annotation for sequence-side context, or to comparative analyses via /bio-protein-clustering-pangenome.

Quick Reference

Input Requirements

Prerequisites:

• Tools available in the active environment (Pixi/conda/system). See docs/README.md for expected tools.
• Reference DB root: set BIO_DB_ROOT to the project or site-local database directory.
• Protein FASTA inputs are available.

Inputs:

• proteins.faa (FASTA protein sequences)

Output

• results/bio-structure-annotation/structures/
• results/bio-structure-annotation/structure_hits.tsv
• results/bio-structure-annotation/structure_report.md
• results/bio-structure-annotation/logs/

Quality Gates

• [ ] Prediction success rate meets project thresholds.
• [ ] Search hit thresholds meet project thresholds.
• [ ] On failure: retry with alternative parameters; if still failing, record in report and exit non-zero.
• [ ] Verify proteins.faa is non-empty and amino acid encoded.
• [ ] Verify Foldseek databases exist under the reference root.

Examples

Example 1: Expected input layout

proteins.faa (FASTA protein sequences)

Troubleshooting

Issue: Missing inputs or reference databases Solution: Verify paths and permissions before running the workflow.

Issue: Low-quality results or failed QC gates Solution: Review reports, adjust parameters, and re-run the affected step.