Journal:Acta Cryst D:S2059798319000214
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The structure of this protein was still unknown and the closest homologue whose structure was determined showed 25% sequence homology only (which made molecular replacement in principle unlikely to be successful). For this reason, experimental phasing was the most likely way to solve it. | The structure of this protein was still unknown and the closest homologue whose structure was determined showed 25% sequence homology only (which made molecular replacement in principle unlikely to be successful). For this reason, experimental phasing was the most likely way to solve it. | ||
This paper (DOI 10.1107/S2059798319000214) describes the approach used to solve in-house the structure of human IBA57 through 5-amino-2,4,6-triiodoisophthalic acid (I3C) high energy remote SAD-phasing. Multiple orientations (each of them corresponding to a different run) of the same P1 (triclinic) crystal have been exploited to acquire sufficient real data multiplicity for successful phasing and thus minimizing the difficulties of merging datasets coming from different crystals. | This paper (DOI 10.1107/S2059798319000214) describes the approach used to solve in-house the structure of human IBA57 through 5-amino-2,4,6-triiodoisophthalic acid (I3C) high energy remote SAD-phasing. Multiple orientations (each of them corresponding to a different run) of the same P1 (triclinic) crystal have been exploited to acquire sufficient real data multiplicity for successful phasing and thus minimizing the difficulties of merging datasets coming from different crystals. | ||
| + | [[Image:IBA57a.jpg|left|500px|thumb|Screenshot of IBA57 crystals]] | ||
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It is also described how the joint use of this I3C derivative and of an in-house native dataset through a SIRAS approach decreases the data multiplicity needed for phasing by almost 50%. | It is also described how the joint use of this I3C derivative and of an in-house native dataset through a SIRAS approach decreases the data multiplicity needed for phasing by almost 50%. | ||
Furthermore, it is illustrated that there is a clear data multiplicity threshold value for success and failure in phasing and how adding further data does not significantly affect substructure solution and model building. The multiplicity threshold for successful phasing appeared, in fact, to be around five, independent of the combination of datasets (runs) used. This value can be reduced to about half through SIRAS by exploiting the isomorphous differences with a second native dataset reaching a successful multiplicity value of less than three. | Furthermore, it is illustrated that there is a clear data multiplicity threshold value for success and failure in phasing and how adding further data does not significantly affect substructure solution and model building. The multiplicity threshold for successful phasing appeared, in fact, to be around five, independent of the combination of datasets (runs) used. This value can be reduced to about half through SIRAS by exploiting the isomorphous differences with a second native dataset reaching a successful multiplicity value of less than three. | ||
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At the time of structure solution coordinates and structure factors were deposited and released in the Protein Data Bank under the accession codes [[5oli]] (for the in-house I3C derivative) and [[6esr]] (for the higher resolution synchrotron structure); at the time of writing the manuscript both entries have been re-refined in order to optimize model quality and statistics and so they have been superseded by [[6qe4]] and [[6qe3]] respectively. | At the time of structure solution coordinates and structure factors were deposited and released in the Protein Data Bank under the accession codes [[5oli]] (for the in-house I3C derivative) and [[6esr]] (for the higher resolution synchrotron structure); at the time of writing the manuscript both entries have been re-refined in order to optimize model quality and statistics and so they have been superseded by [[6qe4]] and [[6qe3]] respectively. | ||
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<b>References</b><br> | <b>References</b><br> | ||
Revision as of 12:27, 13 January 2019
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