I am no expert, but a) a very strong peak 7A from the origin means two
molecules 7A apart?? Most unlikely ..

The first thing to look at is the actual images - Lattice translation
defects usually generate very streaky patterns.
Integration programs can cleverly select a lattice and ignore the
unpredicted pixels - (by the way - why don't the data integration programs
scream when this occurs? )
LTDs usually produce some strange intensity statistics too - what do the
moments/twin tests etc look like?


Otherwise your spacegroup must be wrong, although providing you have got
the right crystalclass, I cant think how that can generate such a Patterson
peak..

Good luck Eleanor
PS - maybe search out another crystal!

On Wed, 12 Feb 2020 at 10:25, Harry Powell - CCP4BB <
0000193323b1e616-dmarc-requ...@jiscmail.ac.uk> wrote:

> Hi
>
> Something else I should have mentioned - in iMosflm you can sum your
> images for viewing only if you have them as  HDF5 or Pilatus CBF (as well
> as summing them for processing if you have HDF5).
>
> Harry
>
> On 12 Feb 2020, at 10:18, Schreuder, Herman /DE <
> herman.schreu...@sanofi.com> wrote:
>
> Hi Daniele,
>
> I agree with Wim that the first thing you should check is your space group
> and especially whether a ncs symmetry element has been mistakenly
> identified as being crystallographic. Since your Patterson peak is along w
> (c-axis), you have to change the space group for processing such, that
> there are no rotation axes or other symmetry elements perpendicular to the
> c-axis any more. If you have a low-symmetry space group, you could also
> process in P1 to be absolutely on the safe side. Than you should run MR in
> this lower symmetry space group.
>
> Concerning lattice translocation defects, almost every case is unique and
> I am not aware of any software able to handle this. Here you will have to
> work out the maths for your particular case yourself and apply the
> correction with e.g. sftools. I am a little puzzled by your 7Å vector in
> your (native?) Patterson maps. I guess, if you translate your protein by 7Å
> it will strongly overlap with itself and I guess the same will be true for
> your ghost map. You should also have a look at your diffraction images,
> perhaps after summing them to 1° slices so become human-interpretable. In
> many cases, LTD is associated with a mix of sharp and fuzzy diffraction
> spots. Seeing those would be a strong indicator that you have the problem,
> but there are cases of LTD where all the spots are sharp. You may also want
> to check for statistical disorder.
>
> Good luck!
> Herman
>
> *Von:* CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> *Im Auftrag von *Wim
> Burmeister
> *Gesendet:* Mittwoch, 12. Februar 2020 08:57
> *An:* CCP4BB@JISCMAIL.AC.UK
> *Betreff:* [EXTERNAL] Re: [ccp4bb] Lattice-translocation defect (LTD)
>
>
> *EXTERNAL : *Real sender is owner-ccp...@jiscmail.ac.uk
>
>
>
> Hello,
>
> do you have some details about the space group ? Did the integration not
> miss any sports ? I would rather think of an ncs close to crystallographic
> symmetry, or maybe some twinning problem.
>
> I guess these are Pilatus data, can you combine the frames into 1 degree
> oscillations and try Mosflm processing to see how the patterns integrate ?
>
> Greetings
>
> Wim
> Le 11/02/2020 à 22:31, Daniele de Sanctis a écrit :
>
> Hi all,
>
> I'm currently dealing with what I think it is a case of LTD (off-origin
> Patterson peak, with vector along w of ~ 7A and electron density map
> showing a "ghost" map shifted by 7 A). I saw there are quite a few cases
> reported in literature  (for example Hare et al, 2006), but what I could
> not find is how I can demodulate the data. Is there any software that can
> be used for this?
>
> Thank you
>
> Daniele
>
> --
> ἀρετή
> ---------------------------------------
> Daniele de Sanctis, PhD
>
> Structural Biology Group
> ESRF, Grenoble, France
> Tel 33 (0)4 76 88 2869
>
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