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Would the CCP4 program BLEND be a suitable initial option? And then the anisotropic server?

Tony.

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On 12 Nov 2014, at 21:29, Robert Keenan <[log in to unmask]<mailto:[log in to unmask]>> wrote:



I have three datasets of varying quality collected from different regions of a single crystal. In each case, the data are anisotropic (from Aimless using CC1/2>0.5):

Dataset 1:  3.5, 3.5 5.5 A
Dataset 2:  4.2, 4.3, 4.8 A
Dataset 3:  3.7, 3.9, 4.4 A

I initially took a simple-minded approach and processed each dataset at the appropriate resolution limit (set 1: 3.5A; set 2: 4.2A; set 3: 3.7A) using XDS/XSCALE as implemented in xia2. The resulting merged dataset seems fine (albeit with ugly stats in the high-res bins because of the anisotropy), and it allowed me to solve the structure (Rfree/Rcryst ~31/26).

Now I am wondering if I can improve the maps further by first applying an ellipsoidal truncation (using the UCLA diffraction anisotropy server) and then scaling/merging the three datasets together. However, it seems that the UCLA anisotropy server only allows input of one dataset at a time, and it outputs merged amplitudes.

Is there some way to obtain the elliptically truncated but unmerged data for each of the three datasets?

More generally, are there preferred strategies for dealing with strongly anisotropic data?

Bob

----------------
Robert Keenan
Associate Professor
Dept. of Biochemistry & Molecular Biology
GCIS W238
University of Chicago
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Chicago, IL  60637
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