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With phases: how two wrongs can sometimes make a right
In isolation, both weak isomorphous/anomalous difference signals from heavy-atom derivatization and phases from partial molecular-replacement solutions for a subset of the asymmetric unit often fall short of producing interpretable electron-density maps. Phases generated from very partial molecular-...
Autores principales: | , , |
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Formato: | Texto |
Lenguaje: | English |
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International Union of Crystallography
2010
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2852306/ https://www.ncbi.nlm.nih.gov/pubmed/20382995 http://dx.doi.org/10.1107/S0907444909048112 |
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author | Roversi, Pietro Johnson, Steven Lea, Susan M. |
author_facet | Roversi, Pietro Johnson, Steven Lea, Susan M. |
author_sort | Roversi, Pietro |
collection | PubMed |
description | In isolation, both weak isomorphous/anomalous difference signals from heavy-atom derivatization and phases from partial molecular-replacement solutions for a subset of the asymmetric unit often fall short of producing interpretable electron-density maps. Phases generated from very partial molecular-replacement models (if generated carefully) can be used to reliably locate heavy-atom sites, even if the signal is not sufficiently strong to allow robust finding of the sites using Patterson interpretation or direct methods. Additional advantages are that using molecular-replacement phases to define the heavy-atom substructure avoids the need for subsequent hand determination and/or origin-choice reconciliation and that the partial model can be used to aid the mask determination during solvent flattening. Two case studies are presented in which it was only by combining experimental and molecular-replacement phasing approaches that the crystal structures could be determined. |
format | Text |
id | pubmed-2852306 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | International Union of Crystallography |
record_format | MEDLINE/PubMed |
spelling | pubmed-28523062010-04-13 With phases: how two wrongs can sometimes make a right Roversi, Pietro Johnson, Steven Lea, Susan M. Acta Crystallogr D Biol Crystallogr Research Papers In isolation, both weak isomorphous/anomalous difference signals from heavy-atom derivatization and phases from partial molecular-replacement solutions for a subset of the asymmetric unit often fall short of producing interpretable electron-density maps. Phases generated from very partial molecular-replacement models (if generated carefully) can be used to reliably locate heavy-atom sites, even if the signal is not sufficiently strong to allow robust finding of the sites using Patterson interpretation or direct methods. Additional advantages are that using molecular-replacement phases to define the heavy-atom substructure avoids the need for subsequent hand determination and/or origin-choice reconciliation and that the partial model can be used to aid the mask determination during solvent flattening. Two case studies are presented in which it was only by combining experimental and molecular-replacement phasing approaches that the crystal structures could be determined. International Union of Crystallography 2010-04-01 2010-03-24 /pmc/articles/PMC2852306/ /pubmed/20382995 http://dx.doi.org/10.1107/S0907444909048112 Text en © Roversi et al. 2010 http://creativecommons.org/licenses/by/2.0/uk/ This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited. |
spellingShingle | Research Papers Roversi, Pietro Johnson, Steven Lea, Susan M. With phases: how two wrongs can sometimes make a right |
title | With phases: how two wrongs can sometimes make a right |
title_full | With phases: how two wrongs can sometimes make a right |
title_fullStr | With phases: how two wrongs can sometimes make a right |
title_full_unstemmed | With phases: how two wrongs can sometimes make a right |
title_short | With phases: how two wrongs can sometimes make a right |
title_sort | with phases: how two wrongs can sometimes make a right |
topic | Research Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2852306/ https://www.ncbi.nlm.nih.gov/pubmed/20382995 http://dx.doi.org/10.1107/S0907444909048112 |
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