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Dear Randy, Thank you very much for answering. I followed your suggestions but, unfortunately, I couldn't get a reasonable electron density map after MR and refinement. First I would look at the data to see if you have ice rings, because the > peak in mean intensity and second moment of the intensity at about 2.25A > resolution suggests an ice ring problem. If so, you should make sure you > don't contaminate the data with spurious large intensities. > > Indeed, the data has ice rings. At first, I required imosflm to remove ice rings, but it didn't happened. So, I re-processed the data in different space groups removing the ice rings. Second, the statistics (e.g. the second moments plot after tNCS correction > in Phaser) would be consistent with a scenario in which you have > pseudosymmetry along with a twin operator that parallels the > pseudosymmetry. If that's true, it's hard to be sure of the symmetry. For > instance, if the structure really is monoclinic, can you be sure you chose > the correct axis to be the 2-fold? > I am not sure. However, I tried two possible axis to be the 2-fold and none of them gave me reasonable maps after MR and refinement. > > Since you have a good model that gives clear MR solutions even in P21, you > can probably process the data in P1 and solve it with 8 copies in the unit > cell. Then you can look at the symmetry of the MR solution (e.g. in > Zanuda) and see whether it obeys any higher symmetry than P1. > I processed data in P1. After MR (with 8 copies in the ASU), it resulted in TFZ=11.6 and LLG=1434. But the map is still bad and high Rwork and Rfree. According to Zanuda, the data should be P21: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | >> 4 | P 1 21 1 | 68.6868 | 0.6289 | 0.5487 | 0.5523 | --------------------------------------------------------------------- | 1 | P 1 | 69.4151 | 0.6171 | 0.5471 | 0.5559 | | 4 | P 1 21 1 | 69.3810 | -- | 0.5482 | 0.5442 | | 11 | P 21 21 21 | 52.0271 | -- | 0.6107 | 0.6178 | --------------------------------------------------------------------- | << 4 | P 1 21 1 | 69.3810 | -- | 0.5482 | 0.5442 | --------------------------------------------------------------------- I processed in P21 using two different unit cells, and MR resulted in TFZ=20.8 and LLG=511, and TFZ=56 and LLG=2867. However, again, no good maps and statistics. Best regards Marcelo Liberato ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1