Cited by 62Enzyme Structure and FunctionProtein Structure and DynamicsComputational Drug Discovery Methods

Assessing the utility of CASP14 models for molecular replacement

Open access
Millán, Claudia, Keegan, Ronan M., Pereira, Joana, Sammito, Massimo D., Simpkin, Adam J., McCoy, Airlie J., Lupas, Andrei N., Hartmann, Marcus D. +2 more·2021·Proteins: Structure, Function, and Bioinformatics

Published version of a preprint

Abstract

The assessment of CASP models for utility in molecular replacement is a measure of their use in a valuable real-world application. In CASP7, the metric for molecular replacement assessment involved full likelihood-based molecular replacement searches; however, this restricted the assessable targets to crystal structures with only one copy of the target in the asymmetric unit, and to those where the search found the correct pose. In CASP10, full molecular replacement searches were replaced by likelihood-based rigid-body refinement of models superimposed on the target using the LGA algorithm, with the metric being the refined log-likelihood-gain (LLG) score. This enabled multi-copy targets and very poor models to be evaluated, but a significant further issue remained: the requirement of diffraction data for assessment. We introduce here the relative-expected-LLG (reLLG), which is independent of diffraction data. This reLLG is also independent of any crystal form, and can be calculated regardless of the source of the target, be it X-ray, NMR or cryo-EM. We calibrate the reLLG against the LLG for targets in CASP14, showing that it is a robust measure of both model and group ranking. Like the LLG, the reLLG shows that accurate coordinate error estimates add substantial value to predicted models. We find that refinement by CASP groups can often convert an inadequate initial model into a successful MR search model. Consistent with findings from others, we show that the AlphaFold2 models are sufficiently good, and reliably so, to surpass other current model generation strategies for attempting molecular replacement phasing.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1002/prot.26214

Cites

46 of 46 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • A post-CASP study found that only two of the tested targets did not have models good enough for molecular replacement.

    “A post-CASP study of the extent to which other targets could have been solved using molecular replacement by Randy Read and colleagues found that only two of those tested did not have models good enough for molecular replacement49.”

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

1 of the 47 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. [37]McCoy AJ, Sammito MD, Read RJ. Possible implications of AlphaFold2 for crystallographic phasing by molecular replacement. bioRxiv. 2021; 2021.05.18.444614. 10.1101/2021.05.18.444614 PMC8725160 34981757 · DOI

Cited by

Sorted by citations

Authors
Millán, C., Keegan, R. M., Pereira, J., Sammito, M. D., Simpkin, A. J., McCoy, A. J., Lupas, A. N., Hartmann, M. D., Rigden, D. J., & Read, R. J.
Affiliations
  • University of Cambridge (GB)
  • Science and Technology Facilities Council (GB)
  • University of Basel (CH)
  • University of Liverpool (GB)
  • Max Planck Institute for Developmental Biology (DE)
Corresponding author
Read, Randy J.
Venue
Proteins: Structure, Function, and Bioinformatics
Publisher
Wiley
Published
2021-08-21
Volume
89
Issue
12
Pages
1752-1769
ISSN
  • 0887-3585 (ISSN-L)
  • 1097-0134
OpenAlex
W3173575423
Cited by
62
References
47
Citations by year
2026: 1 · 2025: 5 · 2024: 13 · 2023: 17 · 2022: 15 · 2021: 11
FWCI
4.25
Type
journal article
Language
en
Open access
Locations
  • Proteins Structure Function and Bioinformatics (publishedVersion, cc-by)
  • bioRxiv (Cold Spring Harbor Laboratory) (acceptedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Apollo (University of Cambridge) (submittedVersion)
  • Science and Technology Facilities Council (submittedVersion, cc-by)
  • Apollo (University of Cambridge) (submittedVersion, cc-by)
  • Apollo
Funders
  • Max-Planck-Gesellschaft
  • Wellcome (209407/Z/17/Z)
  • Biotechnology and Biological Sciences Research Council (BB/S007105/1)
Topics
  • Physical Sciences › Materials Science › Materials Chemistry › Enzyme Structure and Function
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Protein Structure and Dynamics
  • Physical Sciences › Computer Science › Computational Theory and Mathematics › Computational Drug Discovery Methods
Keywords
CASP14, molecular replacement, model evaluation, rigid-body refinement, AlphaFold2, model generation, phasing, model ranking
MeSH terms
Algorithms, Models, Molecular, Magnetic Resonance Spectroscopy, Protein Conformation, Proteins, Software, Crystallography, X-Ray, Computational Biology

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review