Evaluating deep learning based structure prediction methods on antibody-antigen complexes
Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML · Peer-reviewed
DOI: 10.1093/bioinformatics/btag136
Authors: Fromm, Ludaic and Elofsson (Stockholm University); conflicts of interest: none declared. The authors did not develop AlphaFold3, Boltz-1 or Chai-1. pDockQ2, one of the ranking scores compared, comes from the same group (Zhu et al. 2023).
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- Evidence summary: structural hypotheses for experiments: Summary Two new comparisons join the existing docking and FoldBench evidence, both on antibody complexes, and neither ties a prediction to an experiment's outcome. Fromm et al. 2026 generated 200 AlphaFold3 models for each of 110 antibody-antigen complexes deposited after the training cutoff, then asked which model each confidence score picks. Every score a user can compute picked models of about the same quality: mean DockQ 0.375 for ranking confidence, 0.370 for ipTM, 0.369 for pTM, 0.353 for ipSAE and 0.352 for pDockQ2, while the best of the 200 models averaged 0.544. The per-target correlation between score and accuracy stayed at or below 0.247, so within one target the confidence ranking carried little information. Smorodina et al. 2026, a bioRxiv preprint that has not been peer reviewed, ran AlphaFold3, Boltz-2, Boltz-1 and Chai-1 on 106 nanobody-antigen complexes. Sampling raised the best available model for every tool, with median best DockQ rising from 0.24 to 0.68 for AlphaFold3 and from 0.57 to 0.80 for Boltz-2 between 1 and 100 samples, though picking that best sample needs the experimental structure. Confidence tracked accuracy unevenly: the correlation between ipTM and best-sample DockQ was 0.736 for AlphaFold3, 0.665 for Boltz-2 and 0.612 for Chai-1, with 18% of Boltz-2 predictions confident but wrong and 24% of Chai-1 predictions accurate but unconfident. Pairing every nanobody with every antigen showed that confidence does not indicate that an interaction exists at all: average precision for ranking the real pairings above shuffled ones was 0.187 for AlphaFold3, 0.067 for Chai-1 and 0.026 for Boltz-2, against a baseline of about 0.011. The preprint's nanobody set mixes systems inside and outside each tool's training data, and its non-cognate pairings are assumed not to bind rather than tested. A high confidence score is a statement about a predicted structure, not evidence that two molecules interact. (structural-20261009-source-fromm2026: Table 1, sections 2.1 and 2.2; structural-20261009-source-smorodina2026: Results P8, P11, P19 and P36)
- headline_finding: structural-20261009-protocol-fromm2026-abag-model-selection: Headline finding For AlphaFold3 the mean DockQ of the top-ranked model rises only from 0.29 to 0.37 as sampling grows, while the best generated model reaches 0.52. For Boltz-1 and Chai-1 the top-ranked model barely improves with more samples (from 0.12 to 0.14). Scores computed from predicted aligned errors give a mean DockQ of about 0.35 for the selected model against 0.54 for the best model; the same scores computed from the true aligned errors close most of that gap. (Section 3.3 paragraph 1; section 3.6 paragraph 4)
- Relevance of structural-20261009-protocol-fromm2026-abag-model-selection to "Which predicted interfaces or structures are reliable enough to guide my next experiment?": Assessed by Picking the top AlphaFold3 model per antibody-antigen target with a confidence score (structural-20261009-source-fromm2026: Section 2.1; sections 3.3 and 3.6; Table 1)
Models, benchmarks and other records
Configurations (9)
- AlphaFold3, 200 models per target, top model picked by aeiTM: ipTM recomputed from true aligned errors (oracle) (Fromm et al. 2026)
- AlphaFold3, 200 models per target, top model picked by aeRankConf: 0.2 aeTM + 0.8 aeiTM (oracle) (Fromm et al. 2026)
- AlphaFold3, 200 models per target, top model picked by aeTM: pTM recomputed from true aligned errors (oracle) (Fromm et al. 2026)
- AlphaFold3, 200 models per target, top model picked by AlphaFold3 ipTM (Fromm et al. 2026)
- AlphaFold3, 200 models per target, top model picked by AlphaFold3 pTM (Fromm et al. 2026)
- AlphaFold3, 200 models per target, top model picked by AlphaFold3 ranking confidence (0.2 pTM + 0.8 ipTM) (Fromm et al. 2026)
- AlphaFold3, 200 models per target, top model picked by DockQ against the experimental structure (oracle upper bound) (Fromm et al. 2026)
- AlphaFold3, 200 models per target, top model picked by ipSAE (Dunbrack 2025), PAE and distance cut-off 10 Å (Fromm et al. 2026)
- AlphaFold3, 200 models per target, top model picked by pDockQ2 (Zhu et al. 2023) (Fromm et al. 2026)
Protocols (1)
Datasets (1)
Evaluations (9)
- AlphaFold3 top model by aeiTM on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
- AlphaFold3 top model by aeRankConf on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
- AlphaFold3 top model by aeTM on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
- AlphaFold3 top model by DockQ on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
- AlphaFold3 top model by ipSAE on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
- AlphaFold3 top model by ipTM on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
- AlphaFold3 top model by pDockQ2 on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
- AlphaFold3 top model by pTM on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
- AlphaFold3 top model by RankConf on 110 post-cutoff antibody-antigen complexes (Fromm et al. 2026)
Use cases (1)
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22 evidence rows matching the loaded filters
| Property and statement | Original source and location | Review and provenance |
|---|---|---|
| Access and reuse CC BY 4.0 permits redistribution of the article bytes. Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
| Archive note Gzip copy (gzip -n -9) archived in the batch as artifacts/fromm2026-article.xml.gz. Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
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| Artifact url https://www.ebi.ac.uk/europepmc/webservices/rest/PMC13061134/fullTextXML Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
| Doi 10.1093/bioinformatics/btag136 Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
| Extraction method JATS XML parse (xml.etree), by extract/extract_structural.py Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
| Licence CC-BY-4.0 Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
| Media type application/xml Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
| Publication status peer_reviewed Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
| Retrieved at 2026-10-09T21:21:58Z Source metadata | Evaluating deep learning based structure prediction methods on antibody-antigen complexes No field-specific location recorded Version: Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML | catalogued No individual claim review recorded Audit detailsField: Source artifact SHA-256: Hash scope: JATS XML parse (xml.etree), by extract/extract_structural.py |
Sources and history
Release 2026-11-02-a7f03c9e55a5 · Record review: source checked
Primary source retrieved and hashed for the structural hypotheses use-case pass.
Technical metadata and extraction receipts
Stable ID: structural-20261009-source-fromm2026
- areas
- proteins-complexes
- contexts
- research
- url
- https://doi.org/10.1093/bioinformatics/btag136
- artifact url
- https://www.ebi.ac.uk/europepmc/webservices/rest/PMC13061134/fullTextXML
- version
- Bioinformatics 42(4):btag136, 2026; PMC13061134 full-text XML
- retrieved at
- 2026-10-09T21:21:58Z
- artifact sha256
- a7320667ed6f7d8df440d90275d976b91d2fe98411172a79c6a304eb3f02275d
- publication status
- peer_reviewed
- licence
- CC-BY-4.0
- media type
- application/xml
- doi
- 10.1093/bioinformatics/btag136
- source locator
- Full artifact bytes; per-record locators on each record
- access and reuse
- CC BY 4.0 permits redistribution of the article bytes.
- archive note
- Gzip copy (gzip -n -9) archived in the batch as artifacts/fromm2026-article.xml.gz.
- extraction method
- JATS XML parse (xml.etree), by extract/extract_structural.py
- scope note
- Authors: Fromm, Ludaic and Elofsson (Stockholm University); conflicts of interest: none declared. The authors did not develop AlphaFold3, Boltz-1 or Chai-1. pDockQ2, one of the ranking scores compared, comes from the same group (Zhu et al. 2023).