Open AccessAlternative models for two crystal structures of bovine rhodopsin
Author(s) -
Stenkamp Ronald E.
Publication year - 2008
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s0907444908017162
Subject(s) - crystal twinning , crystallography , symmetry (geometry) , group (periodic table) , space (punctuation) , rhodopsin , space group , molecule , crystal structure , symmetry operation , protein data bank (rcsb pdb) , crystal (programming language) , unit (ring theory) , physics , chemistry , mathematics , geometry , stereochemistry , x ray crystallography , computer science , optics , quantum mechanics , diffraction , retinal , biochemistry , microstructure , programming language , operating system , mathematics education
The space‐group symmetry of two crystal forms of rhodopsin (PDB codes 1gzm and 2j4y ; space group P 3 1 ) can be re‐interpreted as hexagonal (space group P 6 4 ). Two molecules of the G protein‐coupled receptor are present in the asymmetric unit in the trigonal models. However, the noncrystallographic twofold axes parallel to the c axis can be treated as crystallographic symmetry operations in the hexagonal space group. This halves the asymmetric unit and makes all of the protein molecules equivalent in these structures. Corrections for merohedral twinning were also applied in the refinement in the higher symmetry space group for one of the structures ( 2j4y ).