Eleanor Dodson wrote:
> You must have a pseudo translation vector of ~ 0.02 0.5 0.0
> That relates solution 1 and 2, and 3 and 4.
>
> That makes it hard to determine space group - there will be absences
> along 0k0 because of the translation so the space group could be P 2i 2
> 2i or P2i 21 2i
> But which ever SG it is thedata with k odd will be weak, and that means
> you will have a higher R factor.
>
> Eleanor
>
>
>
>
> Jerry McCully wrote:
>> Dear all:
>>
>> I am currently refining a structure solved by MAD and
>> somehow the R factor got stuck around 30% with 2.2 resolution.
>>
>> There are four molecules in one ASU. Two had very good
>> density map and the other two were not equally good.
>>
>> I tried using NCS during refinement but it did not help much.
>>
>> Then I checked my data. Actually I found that there are
>> alternate layers of strong and weak reflections. THe crystal is in a
>> thin-plate shape with orthorombic space group.
>>
>> Then I looked at my molecular replacement solution from Phaser using
>> my native data.
>>
>> Actually phaser gave two sets of solutions, which showed
>> slightly different positions.
>>
>> You can also see that there is a translation inside the same set of
>> solution.
>>
>>
>> SOLU SET RFZ=12.8 TFZ=21.4 PAK=0 LLG=452 RFZ=10.7 TFZ=47.9 PAK=0
>> LLG=1693 RFZ=13.0 TFZ=47.6 PAK=0 LLG=2791 RFZ=10.7 TFZ=46.1 PAK=0
>> LLG=4045
>> SOLU 6DIM ENSE ensemble1 EULER 184.052 0.185 175.770 FRAC
>> -0.49889 -0.00218 -0.00000
>> SOLU 6DIM ENSE ensemble1 EULER 225.116 0.167 134.696 FRAC
>> -0.47056 0.49706 0.00051
>> SOLU 6DIM ENSE ensemble1 EULER 359.333 31.677 180.633 FRAC
>> 0.75769 -0.71475 -0.14004
>> SOLU 6DIM ENSE ensemble1 EULER 359.373 31.969 180.711 FRAC
>> 0.73074 -0.21423 -0.14108
>> SOLU SET RFZ=12.8 TFZ=21.4 PAK=0 LLG=452 RFZ=10.7 TFZ=47.9 PAK=0
>> LLG=1693 RFZ=13.0 TFZ=47.6 PAK=0 LLG=2791 RFZ=10.7 TFZ=47.3 PAK=0
>> LLG=4042
>> SOLU 6DIM ENSE ensemble1 EULER 213.115 0.173 146.741 FRAC
>> -0.49931 -0.00269 0.00045
>> SOLU 6DIM ENSE ensemble1 EULER 248.173 0.254 111.665 FRAC
>> -0.47091 0.49661 0.00101
>> SOLU 6DIM ENSE ensemble1 EULER 359.399 31.602 180.578 FRAC
>> 0.75808 -0.71455 -0.13980
>> SOLU 6DIM ENSE ensemble1 EULER 359.378 31.255 180.361 FRAC
>> 0.78370 -0.21555 -0.13830
>>
>>
>> I remember there is a discussion in CCP4bb about the same topic
>> with the focus of pseudo-symmetry or translational pseudo-symmetry.
>>
>> Can anybody give some troubleshooting about my issue?
>>
>> Thanks a lot and have a nice weekend,
>>
>> Jerry McCully
>>
>>
>>
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>>
Hi Jerry,
I am having similar trouble with you. You might want to check out
this paper Acta Cryst.(2005) D61:67-74. It is about lattice-tranlation
defects and how to correct it. Hopefull it is helpful!
Good Luck!
Yuan
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