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 P<sub>1</sub> with 14.4% ( [http://www.rcsb.org/pdb/statistics/histogram.do?mdcat=symmetry&mditem=space_group_name_H-M&numOfbars=200]).
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 ==


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:
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 [http://reference.iucr.org/dictionary/Main_Page IUCr wiki]:


[[iucr:Reflection_conditions|Reflection_conditions]] which explains the topic, and links to lists of the general absences in article [[iucr:Integral_reflection_conditions|Integral_reflection_conditions]], and the absences along the screw axes in [[iucr:Serial_reflection_conditions|Serial_reflection_conditions]]
[[iucr:Reflection_conditions|Reflection_conditions]] which explains the topic, and links to lists of the general absences in article [[iucr:Integral_reflection_conditions|integral reflection conditions]], and the absences along the screw axes in [[iucr:Serial_reflection_conditions|serial reflection conditions]].

Latest revision as of 20:33, 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.