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Re: [ccp4bb]: FALLOFF warnings from truncate
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Pedro...
Maybe your crystal was just anisotropic - was it a thin plate or rod? - the
large differences in scattering mass presented to the beam at different phi
angles can give rise to this anisotropy - or maybe you have one cell axis
significantly longer that the other two???
Either way - it may not present too much of a problem - just be aware of it...
If you use the CCP4 program HKLVIEW, you can look at the diffraction in
different directions and check the extent of the anisotropy...
One nice trick can be to run DREAR from the Shake and Bake program - this
normalises your structure factors (converts Fs to Es) and I seem to remember
being told that it does some sort of anisotropy correction - this is only
needed in extreme cases though...
Hope this helps...
Dave
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Dave Briggs
Bacterial Toxins Group http://www.cryst.bbk.ac.uk/~ebrig02/
School of Crystallography
Birkbeck College tel +44(0)207 631 6835
London, UK
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.....treading the fine line between pride and arrogance...
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