Aniso scaling

Axel T. Brunger brunger at LAPLACE.CSB.YALE.EDU
Tue Sep 24 10:22:46 EST 1996


Did you use X-PLOR for anisotropic scaling?  In X-PLOR(online), 3.843,
you can specify a subrange for computing the anisotropic tensor,
but apply the tensor to ALL reflections (file
/tutorial/xtalrefine/baoverall.inp).


  Axel Brunger

JAMIER at rubens.its.unimelb.edu.au wrote:
> 
> I have a few queries regarding anisotropic scaling of data.
> A  data set was scaled anisotropically ( infinity to 2.2, no sig cut off), and
> then used in the subsequent refinement.  the results looked encouraging:
> a 5% drop in Rcryst, mirrored by a 5% drop in FreeR.  However, when I looked
> at the B-factors, they were significantly higher (20-30 A2) cf. to refinements prior
> to aniso. scaling.
> Does this difference arise from using all reflections when calculating the
> anisotropic scaling?
> It was suggested on the CCP4 bulletin board that anisotropic
> scaling should be performed on a `pruned' data set, eg, 8 to 2.2A, 2sig
> cut off.  But the resulting fob file would then be missing the excluded data.
> However, I would like to refine against all the data.
> 
> Thanks
> J Rossjohn
> St. Vincent's Institute of Medical Research,
> 41 Victoria Parade, Fitzroy,
> Victoria 3065
> Australia
> JAMIER at rubens.its.unimelb.edu.au
-- 
-- 
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| Axel T. Brunger          Dept. Molecular Biophysics and Biochemistry|
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