I expect your space group is getting changed by a program called
POINTLESS, which is generally the entry point for XDS data into a format
that AIMLESS can read. Documentation is here:
http://www.ccp4.ac.uk/html/pointless.html
I'm not sure what interface you are using, but if you can find a way
to get the string "CHOOSE SPACEGROUP P3121" (where "P3121" is your space
group of choice) into the input of POINTLESS, then I think that will do
what you want.
Of course, as long as your scaling is done in the point group of the
space group you want, it might be easier to just change the space group
after scaling with REINDEX.
Remember:
There are 14 Bravais lattices, and this decision must be made before
integrating the spots
There are 12 point groups (for chiral stuff), and this decision must be
made before scaling and merging
There are 65 space groups (for chiral stuff), and this decision must be
made before phasing
There are, of course, a long list of clever ways around these rules, but
in general if you want to change point group, then you will probably
want to do scaling again. If you want to change Bravais lattice then
you probably want to go back to integration (need diffraction images).
But, if you are in the right point group and all you want to do is
change to another space group within that point group, then you can just
change the file header. Unless, of course, you have phases (and a pdb
file counts), then you generally want to "re-do" whatever you did to get
those phases in the new space group (MR, MAD, SAD, MIR, etc.).
That said, if "the programs" are changing your space group from the one
you want, then 9 times out of 10 they are right and you are wrong. Make
sure you look at the log files and documentation long enough to
understand why the automated decision is being made. Its okay to
disagree, but only after you have checked.
-James Holton
MAD Scientist
On 1/24/2016 11:31 AM, Gyl wrote:
> Dear All,
>
> Pardon the newbie question. I processed my data in XDS and scaled in
> Aimless. How can I stop Aimless from changing the space group I picked
> in XDS? Thank you in advance.
>
> Sincerely,
> Gyl
>
>
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