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[ccp4bb]: summary: scalepack failure
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I sent a mail about "scale failure" a while ago and got many feedback.
I really appreciated those poeple for their suggestions.Following is a
summary of the suggestion.
1) It might be wrong index. Reidex!
2) Try lower symmetry P6.
3) Check the orientations of each frame.
4) Try P3, P3(1)22, P3(2)22, P322
5) Check whether the spindle axis is wrong.
I tried these suggestions recently.It should be wrong index! But I
checked each parameters of index carefully, no one is wrong. I tried the
lower symmetry P6 as well as other symmetry suggested. No improvement. In
fact, I never doubtle the symmetry of P6122 myself. I tried some smaller
crystals as well as heavy atom derivatives before, This symmetry gives
successful result. If it is wrong symmetry, all my previous data would have
the same problem. The problem seems to be solved after the beam is alined
and the detector is pulled back to 200mm. As some of you noticed, c is
high,about 196 Å from my previous index result. The error will be
disastrous with even a little beam line deviation. Another cause might be
short distance(150 mm) diffraction with a very big cystal which give too
much crowed and strong spots, although I can not see overlap of spots.
Ms yuan Ping
Macromolecular x-ray Crystallography Group
Institute of Molecular Agrobiology
1 Research Link
National University of Singapore