Evidence map›Paper›PMID 26960122›Full record

ArticleActa crystallographica. Section D, Structural biology2016

Can I solve my structure by SAD phasing? Anomalous signal in SAD phasing.

Thomas C Terwilliger, Gábor Bunkóczi, Li Wei Hung, Peter H Zwart, Janet L Smith, David L Akey, Paul D Adams

Abstract read
In one paragraph

Article in Acta crystallographica. Section D, Structural biology, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 29 papers.

0numbers the graph read from it
0cells of the map it votes in
29citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

29 citing papers in PubMed.

  1. The Untangle Challenge for accurate ensemble models.bioRxiv : the preprint server for biology · 2026
    Article
  2. Crystal structure of a tRNA acceptor-stem mimic at 1.94 Å resolution.Acta crystallographica. Section F, Structural biology communications · 2026
    Article
  3. Article
  4. Article
  5. Article
  6. Native SAD phasing at room temperature.Acta crystallographica. Section D, Structural biology · 2022
    Article
  7. Article
  8. Phosphorus and sulfur SAD phasing of the nucleic acid-bound DNA-binding domain of interferon regulatory factor 4.Acta crystallographica. Section F, Structural biology communications · 2021
    Article
  9. Article
  10. Article
  11. Article
  12. Article
  13. Towards the automation of in situ experimental phasing.Acta crystallographica. Section D, Structural biology · 2020
    Article
  14. Article
  15. SAD phasing of XFEL data depends critically on the error model.Acta crystallographica. Section D, Structural biology · 2019
    Article
  16. Article
  17. Making routine native SAD a reality: lessons from beamline X06DA at the Swiss Light Source.Acta crystallographica. Section D, Structural biology · 2019
    Article
  18. Choosing your (Friedel) mates wisely: grouping data sets to improve anomalous signal.Acta crystallographica. Section D, Structural biology · 2019
    Article
  19. Article
  20. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

Thomas C TerwilligerBioscience Division, Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545, USA.
Gábor BunkócziDepartment of Haematology, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge CB2 0XY, England.
Li Wei HungPhysics Division, Los Alamos National Laboratory, Mail Stop D454, Los Alamos, NM 87545, USA.
Peter H ZwartPhysical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Janet L SmithLife Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.
David L AkeyLife Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.
Paul D AdamsPhysical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.

Funding

PROJECT 5 - DUKE - STRUCTURE VALIDATION AND IMPROVEMENT FOR PROTEINS AND N. ACIDSP01GM063210 · NIGMS · UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB · PI ADAMS, PAUL DAVID · 2001 to 2021
$33.5M
Structure-function studies of alpha-and flavivirusesP01AI055672 · NIAID · PURDUE UNIVERSITY WEST LAFAYETTE · PI KUHN, RICHARD J. · 2003 to 2010
$18.4M
NIAID NIH HHS P01 AI055672NIGMS NIH HHS P01 GM063210NIGMS NIH HHS P01GM063210
6 · The paper itself

Abstract

A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. A simple theoretical framework for describing measurements of anomalous differences and the resulting useful anomalous correlation and anomalous signal in a SAD experiment is presented. Here, the useful anomalous correlation is defined as the correlation of anomalous differences with ideal anomalous differences from the anomalous substructure. The useful anomalous correlation reflects the accuracy of the data and the absence of minor sites. The useful anomalous correlation also reflects the information available for estimating crystallographic phases once the substructure has been determined. In contrast, the anomalous signal (the peak height in a model-phased anomalous difference Fourier at the coordinates of atoms in the anomalous substructure) reflects the information available about each site in the substructure and is related to the ability to find the substructure. A theoretical analysis shows that the expected value of the anomalous signal is the product of the useful anomalous correlation, the square root of the ratio of the number of unique reflections in the data set to the number of sites in the substructure, and a function that decreases with increasing values of the atomic displacement factor for the atoms in the substructure. This means that the ability to find the substructure in a SAD experiment is increased by high data quality and by a high ratio of reflections to sites in the substructure, and is decreased by high atomic displacement factors for the substructure.

Indexed as

AlgorithmsCrystallography, X-RayModels, MolecularProtein ConformationProteinsSignal-To-Noise RatioSoftwareProteinsanomalous phasinganomalous signalSAD phasingsolving structures

Identifiers

PMID26960122
PMCPMC4784666

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.