The model is essentially 100% identical. The structure is of a point mutant that has already been solved.
________________________________________ From: Tim Gruene [t...@shelx.uni-ac.gwdg.de] Sent: Tuesday, July 30, 2013 5:26 AM To: Jeffrey D Brodin Cc: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Twin or underestimation of symmetry -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dear Jeffrey, how complete is you model, i.e. what is the ratio between the number of atoms in the PDB file (without solvent/ ligands) and the expected number of atoms as calculated from the sequence? If a substantial part of the molecule is disordered you may not be able to get a much better model. What is the R-value and Rfree? If you have placed many water atoms you may have hovered out the difference density allowing you to further improve your model. Regards, Tim On 07/29/2013 07:37 PM, Jeffrey D Brodin wrote: > Hi everyone, > > I have a dataset that's been giving me some trouble and wanted to > get your ideas on the best way to proceed. The data extend to ~2.6 > Å and scale integrate/scale well in P622. According to Pointless, > the symmetry is either P622 or P6322, however, neither Molrep norm > Phaser finds molecular replacement solutions in these space groups. > If I run Phaser and let it check all other space groups it finds a > solution in P6122, but I can only refine it to an Rfree value of > ~35%. The data also scales well in P3 and P6 and I get molecular > replacement solutions in space groups of either P31 or P61. > However, the Refinement again stalls at an Rfree value of ~35%. I > tried adding twin refinement in Refmac and it seems to be helping; > The R/Rfree values dropped to 20.9/27.3 and the map appears much > better compared to the previous refinements. The refined twin > fractions are 0.26, 0.24, 0.24 and 0.25. Am I doing something wrong > with the refinement or is this a legitimate way to treat the data. > Thank you in advance for your help. > - -- - -- Dr Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iD8DBQFR97DoUxlJ7aRr7hoRAsfrAKCIEYpOkrVfm/VrkIn+Jn9NZ16swACguGLe G1ZAwYDXmvyx/jK0iE7VjZo= =q8Ki -----END PGP SIGNATURE-----
