Dear experts, Yes, you were right the data is twined and shows 1 merohedral twin operator. Now I am performing twin refinement, hope the refinement statistics will improve. Thank you very much for your valuable suggestions.
Regards DCB On Sun, Oct 13, 2013 at 3:01 PM, Kay Diederichs < kay.diederi...@uni-konstanz.de> wrote: > Dear Dilip, > > yes, your data probably are ok, at least based on the value of I/sigma=3.2 > in the highest shell (and based on that, the data could even be used to 1.6 > or maybe 1.5A). The overall and the highest shell Rmerge actually do not > carry much information. It would be rather interesting to know the Rmerge > (or better, Rmeas) in the lowest resolution shell - it should be less than > 5% (ideally 2%). > > You have not answered my question, probably because its meaning was not > clear. What I mean is: in space group P3(2)21 and relatives twinning may > (and often does) occur. If the twinning fraction is low to medium (0.05 to, > say, 0.25), you have no problem with solving the structure and refining it. > But R/Rfree may be stuck, because e.g. with a twin fraction of 0.25, your > model, even if ideal, can only explain 75% of the diffracted intensity; the > remaining 25% will increase the R-factors and lead to unexplainable > difference density blobs. > > The remedy is to analyse the twinning properties with a tool like > phenix.xtriage, and to switch on twin refinement in phenix.refine if > phenix.xtriage tells you that the data is twinned. The analysis is quite > reliable because you can even give your current model to phenix.xtriage . > > hope that helps, > > Kay > > On Sun, 13 Oct 2013 13:07:29 +0530, Dilip Badjugar <dilip....@gmail.com> > wrote: > > >Dear experts, > > > >Thank you very much for your valuable the suggestions. Dear Tim, the > >electron density map is good and fitted well. Krishnaswamy sir, there are > >some unmodelled blobs with positive density, I have added respective ions > >and refined the model using phenix.refine (Rf- 20.56 and Rfree- 25.76). > > Now the question, what is the actual resolution of the data? When I > scaled > > to 1.7� resolution the data statistics is as follows: > > > >Rmerge- 25.5 (239)a > > > > I/sigmaI- 10 (3.2) > > > > > > Completness-100 > >(100) > > > > Multiplicity 11.8 (12.1) > > > >a - indicate the values in the outer shell (1.7-1.79 �) > > > >The Rmerge at 3.1 � resolution is 11.5 % while at 1.7 � it is 239%. Do I > >have enough data to justify 1.7 � resolution? Are those Rfactor values are > >justified with this resolution?Thanking you > > > >DCB > > > > > >On Sun, Oct 13, 2013 at 12:03 PM, Kay Diederichs < > >kay.diederi...@uni-konstanz.de> wrote: > > > >> Are you certain that the data are not twinned? > >> > >> HTH > >> > >> Kay > >> > >> > > > > > >-- > >Mr.Dilip C. Badgujar, > >Senior Research Fellow, > >ACTREC, > >Tata Memorial Center, > >Sector-22, Kharghar, > >Navi Mumbai. > >Pin-410210 > > > > > -- Mr.Dilip C. Badgujar, Senior Research Fellow, ACTREC, Tata Memorial Center, Sector-22, Kharghar, Navi Mumbai. Pin-410210
