Symmetry and space groups: Difference between revisions
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There are 230 space groups, 65 of which accessible to proteins. | There are 230 space groups, 65 of which accessible to proteins. | ||
Empirically, P2<sub>1</sub>2<sub>1</sub>2<sub>1</sub> is the space group which occurs most often (23%) in the [http://www.rcsb.org PDB]; second place is | Empirically, P2<sub>1</sub>2<sub>1</sub>2<sub>1</sub> is the space group which occurs most often (23%) in the [http://www.rcsb.org PDB]; second place is P2<sub>1</sub> with 14.4%, then comes C2 (9.0%) ( [http://www.rcsb.org/pdb/statistics/histogram.do?mdcat=symmetry&mditem=space_group_name_H-M&numOfbars=200]). | ||
== Reflection conditions == | == Reflection conditions == | ||
Revision as of 19:31, 11 May 2008
Space group operators can be found here: http://www.embl-hamburg.de/~pinotsis/spacegroup.html
The crystallographic toolbox is at [1]. Its predecessor, SgInfo, is here.
Facts about space groups
There are 230 space groups, 65 of which accessible to proteins.
Empirically, P212121 is the space group which occurs most often (23%) in the PDB; second place is P21 with 14.4%, then comes C2 (9.0%) ( [2]).
Reflection conditions
These are explained and listed in Section 2.2.13 of International Tables of Crystallography, Volume A . If this is not on your desk, check out the IUCr wiki:
Reflection_conditions which explains the topic, and links to lists of the general absences in article Integral_reflection_conditions, and the absences along the screw axes in Serial_reflection_conditions