International
Tables for Crystallography Volume G Definition and exchange of crystallographic data Edited by S. R. Hall and B. McMahon © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. G. ch. 3.6, p. 190
Section 3.6.7.6. Crystal symmetry
P. M. D. Fitzgerald,a* J. D. Westbrook,b P. E. Bourne,c B. McMahon,d K. D. Watenpaughe and H. M. Bermanf
a
Merck Research Laboratories, Rahway, New Jersey, USA,bProtein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers, The State University of New Jersey, Department of Chemistry and Chemical Biology, 610 Taylor Road, Piscataway, New Jersey, USA,cResearch Collaboratory for Structural Bioinformatics, San Diego Supercomputer Center, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0537, USA,dInternational Union of Crystallography, 5 Abbey Square, Chester CH1 2HU, England,eretired; formerly Structural, Analytical and Medicinal Chemistry, Pharmacia Corporation, Kalamazoo, Michigan, USA, and fProtein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers, The State University of New Jersey, Department of Chemistry and Chemical Biology, 610 Taylor Road, Piscataway, New Jersey, USA |
The categories describing symmetry are as follows:
Data items in the SYMMETRY category are used to give details about the crystallographic symmetry. The equivalent positions for the space group are listed using data items in the SYMMETRY_EQUIV category. These categories are used in the same way in the core CIF and mmCIF dictionaries, and Section 3.2.4.4
can be consulted for details.
The current version of the mmCIF dictionary includes the SPACE_GROUP categories that were derived from the symmetry CIF dictionary (Chapter 3.8
) and included in version 2.3 of the core CIF dictionary. At the time of writing, macromolecular applications have not yet begun to make use of these new categories.
Data items in these categories are as follows:
The bullet () indicates a category key. The arrow (
) is a reference to a parent data item. Items in italics have aliases in the core CIF dictionary formed by changing the full stop (.) to an underscore (_) except where indicated by the
symbol.
The data item _symmetry.entry_id has been added to the SYMMETRY category to provide the formal category key required by the DDL2 data model.