Intensity statistics in twinned crystals with examples from the PDB.
By A. Lebedev, A. Vagin, G. Murshudov. 2006
52 citations recorded by the source corpus.
Entries deposited in the Protein Data Bank as of February 2004 for which both model and X-ray data were available were analysed to identify cases of twinning using such simple statistics as the R factor between potential twin-related reflections. Careful consideration of all identified twins showed that in many cases twinning was ignored during structure solution and refinement. Manual analysis of the models showed that twinning often occurs in association with rotational pseudosymmetry parallel to the twinning operator. The coexistence of these two phenomena complicates the detection and diagnostics of twinning using currently available twinning tests. It was concluded that a twinning-detection step should be incorporated in every stage of structure analysis from data acquisition to refinement and validation.
Subfields: Materials Chemistry, Molecular Biology
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In Materials Chemistry
- Randy J. Read
- Paul D. Adams
- G. Murshudov
- A. McCoy
- T. Croll
- Martyn D. Winn
- Pavel V. Afonine
- G. Bunkoczi
In Molecular Biology
- Randy J. Read
- Paul D. Adams
- G. Murshudov
- A. McCoy
- Martyn D. Winn
- T. Croll
- G. Bunkoczi
- T. C. Terwilliger
Citations in the corpus
- Overview of the CCP4 suite and current developments (2011, background): “REFMAC5 will also now refine against twinned data (Lebedev et al., 2006), automatically recognising the twin laws and estimating the corresponding twin fractions.”
- Macromolecular crystal twinning, lattice disorders and multiple crystals (2008, methodology): “(101) grouped cases of undetected twinning as their schematic plot here shows via their R factor test.”
- Crystal structures (2004, unknown): “(i) Identify potential (pseudo)merohedral twin operators by analyses of cell/space-group combination using the algorithm developed by Lebedev et al. (2006).”
- A New Generation of Crystallographic Validation Tools for the Protein Data Bank (2011, methodology): “Therefore, it is advisable to also check the atomic model for potential higher symmetry, either by examining the coordinates, as done in WHAT_CHECK (Hooft et al., 1996a) or LABELIT (Poon et al., 2010), or the calculated structure factors with the RvR test (Lebedev et al., 2006).”