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Tracking reflections through cryogenic cooling with topography
Author(s) -
Lovelace Jeffrey J.,
Murphy Cameron R.,
Pahl Reinhard,
Brister Keith,
Borgstahl Gloria E. O.
Publication year - 2006
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889806012763
Subject(s) - mosaicity , monochromatic color , optics , synchrotron radiation , reflection (computer programming) , materials science , radiation , diffraction , perpendicular , tracking (education) , physics , x ray crystallography , computer science , geometry , mathematics , programming language , psychology , pedagogy
The mosaic structure of a single protein crystal was analyzed by reflection profiling and topography using highly parallel and monochromatic synchrotron radiation. Fine‐ϕ‐sliced diffraction images (0.002° stills) were collected using a conventional large‐area CCD detector in order to calculate reflection profiles. Fine‐ϕ‐sliced topographic data (0.002°) stills were collected with a digital topography system for three reflections in a region where the Lorentz effect was minimized. At room temperature, several different mosaic domains were clearly visible within the crystal. Without altering the crystal orientation, the crystal was cryogenically frozen (cryocooled) and the experiment was repeated for the same three reflections. Topographs at cryogenic temperatures reveal a significantly increased mosaicity, while the original domain structure is maintained. A model for the observed changes during cryocooling is presented.