Dear All,
I agree entirely with Tim - looking at the images often gives a lot of information as to what is going on with problematic data sets. Also, however, not wishing to use the bb as an advertising platform, we (xia2 / DIALS developers) find that multiple lattices are remarkably common these days, particularly with problematic data sets. You can get a very good idea by importing the data into DIALS, finding spots, then looking at the reciprocal lattice: this will give you a very clear idea of what is going on very quickly.
For details on how best to do this please drop us a line on [log in to unmask] as some detail on the nature of the problem would be helpful.
Thanks & best wishes Graeme
-----Original Message-----
From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Tim Gruene
Sent: 14 March 2016 09:35
To: ccp4bb
Subject: Re: [ccp4bb] possible twinned data
Dear Jarrod,
did you inspect the images if you can see multiple lattices? in case of pseudo-merohedral twinning you would best look at high resolution reflections.
What do you mean by 'but these will not refine Rfree'? Did you try twin refinement with refmac5?
Best,
Tim
On Sunday, March 13, 2016 11:56:50 PM Jarrod Mousa wrote:
> Hi all,
>
> I have two data sets for a protein that both index and scale into
> P212121 and process easily in imosflm, yet AIMLESS and Xtriage suggest
> twinning, although no laws fit P212121. I tried indexing into P1 and
> Xtriage finds three possible pseudo-merohedral twin laws h-k-l,
> -h,k-l, and -h,-k,l. I can find solutions easily in Phaser, but these
> will not refine Rfree. I am wondering what the best approaches are to
> find the correct spacegroup and try to solve the structure correctly?
>
> thanks,
>
> Jarrod Mousa
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Dr. Tim Gruene
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