[phenixbb] refine structure with mtz file in P212121 or P222?
nechols at lbl.gov
Fri Sep 5 09:02:19 PDT 2014
On Fri, Sep 5, 2014 at 8:54 AM, Wei Shi <wei.shi118 at gmail.com> wrote:
> I am working with a protein-ligand complex structure. The data was indexed
> with XDS and mtz file is generated using Phenix---Reflection
> tools---Reflection file editor. The space group used was P222. Then, I used
> the Phenix---Molecular replacement to find a solution (try all possible in
> same pointgroup), and the MR solution was in space group P212121. And then,
> I reindexed the data in XDS using space group P212121 and then generate the
> mtz file in space group P212121. So, I have two mtz file, in space group
> P212121 and P222.
> When I refine the MR solution with the different mtz files, the map
> generated is not same for the ligand. The statisitcs is better with P222
> mtz file than P212121 mtz file. I am wondering why the density for the
> ligand and the statistics is different using mtz file in different space
> groups and which mtz file should I use to get the final structure model.
Why did you run XDS again? You shouldn't need to do this, and if you
really did reindex, that could explain why it's not working the way you
expect. The MR solution already corresponds to the indexing in the P222
file - the only thing that is changing is what space group is being used
internally. All you need to do is change the space group in the MTZ file
to P212121, which you can also do in the reflection file editor.
(Actually, you shouldn't even need to do that in order to run
phenix.refine, since you can tell it to use P212121, and I suspect it will
output the *_data.mtz file with the new space group which you can use from
then on.) Don't reindex, don't change anything else.
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