[phenixbb] refinement with twinning
pafonine at lbl.gov
Wed Feb 16 13:06:31 PST 2011
did you generate free-R flags using phenix.refine? If not, then try this:
- create free-R flags from scratch using phenix.refine;
- run ~10 refinement macro-cycles with the new flags. If the R-factors
are similar, then this is what it is.
How the maps look like?
Have a look at page #123 here:
Let me know if you have questions.
On 2/16/11 11:52 AM, alexander.singer at utoronto.ca wrote:
> Hi -- I have a twinned data set -- approximate twinning fraction of
> 0.4. I decided to try to try twinned refinement using phenix.refine
> in what would seem to be the appropriate manner -- from the "All
> Parameters" menu, I select twinning, hit "Run Xtriage now" on my mtz
> file, it gives me the input to the "Twin Law", I keep the rest of the
> values the same (gave no Anisotropy correction), hit OK, then run 3
> cycles of refinement. The only thing is that the Rwork/Rfree values
> are really very good, almost too good to be true -- for my 1.7 A
> refinement, I have values of 12.4 and 14.8%, respectively for Rwork
> and Rfree. Is there anything that I may be doing wrong yielding R
> values which are artifically too low?
> Thanks for your help
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