Averaged kick maps: less noise, more signal...and probably less bias
Use of reliable density maps is crucial for rapid and successful crystal structure determination. Here, the averaged kick (AK) map approach is investigated, its application is generalized and it is compared with other map-calculation methods. AK maps are the sum of a series of kick maps, where each...
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Published in | Acta crystallographica. Section D, Biological crystallography. Vol. 65; no. 9; pp. 921 - 931 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
5 Abbey Square, Chester, Cheshire CH1 2HU, England
International Union of Crystallography
01.09.2009
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Subjects | |
Online Access | Get full text |
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Summary: | Use of reliable density maps is crucial for rapid and successful crystal structure determination. Here, the averaged kick (AK) map approach is investigated, its application is generalized and it is compared with other map-calculation methods. AK maps are the sum of a series of kick maps, where each kick map is calculated from atomic coordinates modified by random shifts. As such, they are a numerical analogue of maximum-likelihood maps. AK maps can be unweighted or maximum-likelihood (sA) weighted. Analysis shows that they are comparable and correspond better to the final model than sA and simulated-annealing maps. The AK maps were challenged by a difficult structure-validation case, in which they were able to clarify the problematic region in the density without the need for model rebuilding. The conclusion is that AK maps can be useful throughout the entire progress of crystal structure determination, offering the possibility of improved map interpretation. |
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Bibliography: | istex:74CB478F8A5796930DCBA175BDB72277BC5D3D34 ark:/67375/WNG-LNCDKS9G-Z ArticleID:AYDDZ5160 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 1399-0047 0907-4449 1399-0047 |
DOI: | 10.1107/S0907444909021933 |