For sure you could do it by these softwares with occ. set to 1/2 (and in case some restrictions need to be released),
if what you mentioned were the TRUTH.

But before doing this, you may want to check the possibilities of 1) misindexing and 2) twinning. MR solution with 1/2 z translation fit as well does not have to mean a new solution nor imply that crystal pathology!

Hey all,

I have a structure where two (identical) half molecules occupy one unit cell but are shifted by half a unit cell translation. I would like to refine them concurrently with global occupancy for each protein fixed to 1/2 initially (maybe relax that later). Is that possible in refmac and how? How about phenix, CNS?

Thank you.


Andreas



Some more details for those interested in crystal pathologies. A fraction of the unit cells making up the crystal are shifted by half a unit cell translation in a statistic manner (peak in native Patterson at 0.5z). The structure was solved by MR with one molecule per au but doesn't refine. There is good density for the MR solution, but the solution shifted by 1/2 z fits the density nearly as well.



--
       Andreas Förster, Research Associate
       Paul Freemont & Xiaodong Zhang Labs
Department of Biochemistry, Imperial College London

Lijun Liu, PhD
Institute of Molecular Biology
HHMI & Department of Physics
University of Oregon
Eugene, OR 97403
541-346-5176



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