Trigonal system

[yong <yxiong@chemistry.ohio-state.edu>]

***  For details on how to be removed from this list visit the  ***
***    CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html    ***

Dear all,

        I got a decent set of data indexed in P31, resolution 1.7Å, >90%
completeness and Rsym 5.3 with ~6 fold redendency (yes, a full 360
degree data collected!). It's for a 10-mer oligonucleotide and a drug
complex. Rfactor stucked at ~30% (Rfree ~35%) with vague density for the
drug. The moment I put the drug in the R shoots up. The structure was
determined in AMORE. Then I tried to use EPMR and 'funny' things
happened. I got 6 differnet solutions (not symetry mates and colliding
with each other) with correlation >0.8 and all packs perfectly well in
the cell indevidually. Refinement preceded with each one of them. And,
each one behaves very similar to the above AMORE solution. A similar
problem happened with another structure with space group R32. Dose any
one have this kind of experience? Are there some fundamentals I missed
about the Trigonal system or I just have to exhaust the search? Thanks.

Yong