On 27 Aug 2010, at 10:55, Petr Kolenko wrote: > Dear crystallographers, > > I have a structure at 3.3A resolution, 16 identical chains in AU, merohedral > twinning present. I started to refine using NCS restraints with chain A as a > reference chain. Current Rwork/Rfree is 21/25. There is almost nothing to > refine manually in whole structure now. But, refinement without NCS > restraints results in Rwork/Rfree of about 17/28. What should I do? Or is it > possible to deposit the structure refined using NCS restraints in final > refinement?
This seems like a really well-done NCS refinement; using the multi-fold NCS is allowing you to get what is an excellent Rfree and Rwork-Rfree gap for 3.3A data. Definitely deposit the NCS-restrained version; refining without NCS restraints just increases the number of parameters by a factor sixteen and spends most of those on fitting noise. 1% Ramachandran outliers at 3.3A also seems entirely reasonable. Tom
