Pseudo translation doesnt seem too much of a problem if the model is OK.
MOLREP uses it within the search, phaser seems not to mind too much for
a general translation..
I dont know about pathological cases where the crystal is very near but
not quite C centred, ie the translation is quite special like in this
case with t = (1/2,0.~1/4)
On 02/09/2011 11:03 PM, Roberts, Sue A - (suer) wrote:
> I have used phaser to successfully solve a structure in P2x2x2x that had pseudo-translational symmetry. It was unable to correctly choose the space group, but after running phaser in all 8 possible space groups and inspecting the best solutions in each the correct solution was clear. Furthermore, it was the only MR program that worked. Was I just lucky?
>
> Sue
>
>>
>> On 9 Feb 2011, at 22:27, Phil Jeffrey wrote:
>>
>>> Is there a program that does ? I was under the impression that they were all equally good/bad at this, because any solution that agrees with the PTS has quite a high score and any solution that doesn't has a low score, irrespective of the correctness of the placement of the molecules.
>>>
>>> In one case that ritually defeats me with quite strong pseudo-centering, this seems to be true for heavy atom searches also.
>>>
>>> Phil Jeffrey
>>> Princeton
>>>
>>> On 2/9/11 5:08 PM, Jon Schuermann wrote:
>>>> I would NOT use Phaser for MR with PTS present. It doesn't handle it
>>>> correctly yet, since the likelihood targets don't account for PTS.
>>>> Others may be able to explain it better.
>>
>
> Dr. Sue A. Roberts
> Dept. of Chemistry and Biochemistry
> University of Arizona
> 1041 E. Lowell St., Tucson, AZ 85721
> Phone: 520 621 8171
> [log in to unmask]
> http://www.biochem.arizona.edu/xray
>
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