Re: [ccp4bb] MTZ cell troubles after sortmtz reindexing from P321 to C2

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Subject: Re: MTZ cell troubles after sortmtz reindexing from P321 to C2
From: "Winter, G (Graeme)" g {- dot -} winter {- at -} DL {- dot -} AC {- dot -} UK
Date: 2008-03-07

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Subject: Re: MTZ cell troubles after sortmtz reindexing from P321 to C2
From: "George M {- dot -} Sheldrick" gsheldr {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2008-03-07

Subject: Re: MTZ cell troubles after sortmtz reindexing from P321 to C2
From: Phil Evans pre {- at -} MRC-LMB {- dot -} CAM {- dot -} AC {- dot -} UK
Date: 2008-03-07

As Graeme says, Pointless should sort this out for you, either from
CCP4 pre-release,
or from ftp://ftp.mrc-lmb.cam.ac.uk/pub/pre

Phil

On 7 Mar 2008, at 20:25, Winter, G (Graeme) wrote:

> Hi Pietro,
>
> I would use pointless for this - it will correctly reindex the
> reflections and sort them to boot. You can specify the correct
> pointgroup and reindex operator to reindex the reflections, and (I am
> 99% sure) pointless will compute the correct unit cell...
>
> You can find recent versions of pointless which do this, and
> documentation on how to do this, on the ccp4 prerelease pages.
>
> Cheers,
>
> Graeme
>
> -----Original Message-----
> From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of
> Pietro Roversi
> Sent: 07 March 2008 18:18
> To: CCP4BB@JISCMAIL.AC.UK
> Subject: [ccp4bb] MTZ cell troubles after sortmtz reindexing from P321
> to C2
>
> Dear all,
> after much sweat and grief I managed to index my data in
> P321 but looking at the symmetry I think they might be C2: reindexing
> from P321 to C2 with the 2h+k, k, l operator in sortmtz produces the
> right cell (and yes I did tick the "Reduce reflexions to the
> asymmetric
> unit" button so that noreduce is not among the sortmtz keywords):
>
> P321 209.3168 209.3168 40.6822 90.0000 90.0000 120.0000
> C2 362.5473 209.3168 40.6822 90.0000 90.0000 90.0000
>
> But: scala then decides that the asymmetric unit is not the right one
> and it mysteriously changes cell parameters (which I think points to a
> bug in the sortmtz process of reindexing):
>
> Reciprocal space symmetry:
> Space group: "C 1 2 1" Point group: "PG2" Laue group: "2/m"
> Reference asymmetric unit: "k>=0 and (l>0 or (l=0 and h>=0))"
> (change of basis may be applied)
>
> and I end up with this C2 cell in the mtz output from scala:
>
> 285.9320 285.9320 40.6824 90.0000 90.0000 90.0000
>
> I have tried OUTPUT ORIGINAL ans some such in scala but to no avail.
>
> Now please don't all tell me to go back and reindex-reintegrate these
> images - although I might have to do it to get the best out of these
> data once I am convinced they are monoclinic.
>
> Rather, I would appreciate suggestions on what program to feed the
> multirecord mtz to sort its asymmetric unit in C2 so that scala does
> not
> play tricks on me; or what keyword to feed scala to keep reflexions in
> the current asymmetric unit (and use cad or sftools afterwards on the
> scaled/merged file)
>
> Thanks
>
> Pietro
>
>
>
> --
> Pietro Roversi
> Sir William Dunn School of Pathology, Oxford University South Parks
> Road, Oxford OX1 3ER, England UK Tel. 0044-1865-275385

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Previous message:
Subject: Re: MTZ cell troubles after sortmtz reindexing from P321 to C2
From: "Winter, G (Graeme)" g {- dot -} winter {- at -} DL {- dot -} AC {- dot -} UK
Date: 2008-03-07