[ccp4bb]: f'' and group refinement in CNS

[Ricardo Aparicio <aparicio@lnls.br>]

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Dear all:

    I am trying to get phases for a protein crystallized with CdCl2
(0.2M). I am searching for HA sites on an Eu(NO3)3 derivative by SAD.
Because the crystal contains Cd in adition to the Eu used in soaking, I
have found some rigid arranges that appears to be Cd-Eu-Cd (the
distances between Cd-Eu are ~2.6A, so I think they are not satelite
peaks).
    I have 2 questions:

1) how can I set f' and f'' values for Eu and Cd  in the same
sad_phase.inp file? Do I need to do this (.sdb file already contains
information about the site type)? Another point is that the logfile
shows 0 for f' and a strange value for f'' (they are not being refined).

2) Is it a good idea to refine this "arrange" as a group ?


    Thank you very much in advance. Any help would be very appreciated.


Ricardo


===========================================================
Ricardo Aparicio
PhD Student at the Brazilian Synchrotron LNLS - http://www.lnls.br
Protein Crystallography Group
Phone +55(19)2874520 / Fax +55(19)2874632