Seeing but not believing: the structure of glycerol dehydrogenase initially assumed to be the structure of a survival protein from Salmonella typhimurium.
Acta Crystallogr D Struct Biol
; 73(Pt 7): 609-617, 2017 Jul 01.
Article
em En
| MEDLINE
| ID: mdl-28695861
ABSTRACT
The determination of the crystal structure of a mutant protein using phases based on a previously determined crystal structure of the wild-type protein is often a straightforward molecular-replacement protocol. Such a structure determination may be difficult if there are large-scale structural differences between the wild-type and mutant proteins. In this manuscript, an interesting case is presented of the unintentional crystallization of a contaminant protein which shared some structural features with the presumed target protein, leading to difficulties in obtaining a completely satisfactory molecular-replacement structure solution. It was not immediately evident that the initial structure solution was incorrect owing to the poor quality of the X-ray diffraction data and low resolution. The structure was subsequently determined by improving the quality of the data and following a sequence-independent MarathonMR protocol. The structure corresponded to that of glycerol dehydrogenase, which crystallized as a contaminant, instead of the presumed mutant of a survival protein encoded by Salmonella typhimurium. The reasons why a solution that appeared to be reasonable was obtained with an incorrect protein model are discussed. The results presented here show that a degree of caution is warranted when handling large-scale structure-determination projects.
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MEDLINE
Assunto principal:
Salmonella typhimurium
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Desidrogenase do Álcool de Açúcar
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Proteínas de Bactérias
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Cristalografia por Raios X
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Cristalização
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article