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Hi,

We are encountering  a strange problem w/ Refmac5 rigid body refinement
(it may happen with other types of refinement as well, we haven't
checked).

We have 3 isomorphous data sets (same protein, different ligands).
Space group 209 (F 4 3 2), a=b=c=181 A.  Data were processed with
d*TREK, and all 3 crystals gave similar statistics; resolutions range
from 1.65-1.8 A.

We run these data through ImportScaled (ccp4i) to generate the mtz
files and then run the rigid body refinement, using in all cases the
same starting coordinate file.

For two of the datasets, the rigid body refinement fails; in the log
file, just after the program lists all the different scattering types
(loop over _atom_type_symbol), we find the following:

 Number of reflections in file      26622
 Number of reflection read           25450
 1error in ssyev_mo
 Problem in aniso_eigens 1

The refinement runs normally for the 3rd dataset (as well as for a
bunch of earlier datasets), with the corresponding position of the log
file containing a message like this:

 Number of reflections in file      28811
 Number of reflection read          26470
===> Warning: No anisotropic scale factor for this space group
 ---------------------------------------------------------
===> Warning: Cubic space groups cannot have overall anisotropic B-value
===> Warning: Isotropic overall B-values will be refined


We've looked closely at the import step, and in all cases we're
specifying the space group correctly. The failure occurs regardless of
the resolution range of the data used, and with both simple and Babinet
solvent treatment.

 Does anyone have any clues as to what might be going on?

Thanks,

Pat

------------------------------------------------------------------------
---------------
Patrick J. Loll, Ph. D.                                         (215) 762-7706
Associate Professor                                     FAX: (215) 762-4452
Department of Biochemistry & Molecular Biology
Director, Biochemistry Graduate Program
Drexel University College of Medicine
Room 10-102 New College Building
245 N. 15th St., Mailstop 497
Philadelphia, PA  19102-1192  USA

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