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On Monday, 22 July 2013, Katherine Donovan wrote: > Hi All, > > I have a data set that was collected to about 2.2A, which I have processed in either P21 (to 2.4 A) or C2221 (2.25A). So I'm confused. You may not know what the spacegroup is, but you are processing the same spots either way. Why would you choose different resolutions for the two processing runs? > I am unsure which space group is more correct. > > I have a higher symmetry space group with higher resolution and average statistics or a lower symmetry space group with lower resolution and great statistics. By "great statistics", do you mean the refined R/Rfree in P21? But you refined that model as a twin, which means that the R factors are expected to be lower. Refining as a twin always produces lower R factors, whether or not the structure really is twinned. It doesn't make sense to me that you would compare at two different resolutions. It's the _same data_ in either case. If you refine two different models against the same data, then you have a legitimate basis on which to compare them. This way - not really. Which brings up the point that something seems to have gone wrong in one of your processing runs. Both runs claim mean (I/sigI) in the outer shell is 2.0, but in one case this is for the 2.4A shell and in the other case it's for the 2.2A shell. That is unlikely to be correct. I/sigI should not depend on the Laue group. If it were me, I'd forget about monoclinic. Also I'd try to push the data processing in orthorhombic to a bit higher resolution. Mean I/sig(I) of 2 in the 2.2A shell leads me to think you would still be adding information from reflections at 2.1A or even 2.0A. Ethan > The statistics provided by aimless below. > > > Any help would be hugely appreciated. > > Thanks, > > Katherine > > > > > P21 > AIMLESS > P21 and cut the data to 2.4A for a Mn I/sd > 2. > > Average unit cell: 74.68 130 129.2 90 106.8 90 > Overall InnerShell OuterShell > Low resolution limit 48.09 48.09 2.44 > High resolution limit 2.40 13.15 2.40 > Rmerge (within I+/I-) 0.085 0.038 0.581 > Rmerge (all I+ and I-) 0.099 0.042 0.687 > Rmeas (within I+/I-) 0.117 0.053 0.792 > Rmeas (all I+ & I-) 0.116 0.050 0.798 > Rpim (within I+/I-) 0.080 0.037 0.534 > Rpim (all I+ & I-) 0.059 0.026 0.405 > Rmerge in top intensity bin 0.045 - - > Total number of observations 352569 2057 17425 > Total number unique 92184 569 4538 > Mean((I)/sd(I)) 9.6 23.6 2.0 > Mn(I) half-set correlation CC(1/2) 0.995 0.995 0.648 > Completeness 100.0 97.2 100.0 > Multiplicity 3.8 3.6 3.8 > > PHENIX – XTRIAGE > One possible pseudo merohedral twin operator > 2-fold axis > h, -k, -h-l > > <I**2>/<I>**2 = 2.032 > <F>**2/<F**2> = 0.787 > <|E**2-1|> = 0.734 > <|L|>, <L**2> = 0.490, 0.321 > Multivariate Z score L-test = 0.616 > > NZ test = Maximum deviation acentric = 0.007 > Maximum deviation centric = 0.051 > L test = Mean L = 0.490 > > Estimated twin fraction: > 0.450 (Britton analyses) > 0.477 (H-test) > 0.478 (Maximum likelihood method) > > Likely point group of the data is C 2 2 2 > > Analysis of the systematic absences indicates a number of likely space group candidates: > C 2 2 21 > > Patterson analysis of peak with length larger than 15 Angstrom: > Frac. Cood = 0.00, 0.166, 0.00 > Distance to origin = 21.530 > Height (origin = 100) = 3.787 > p-value (height) = 9.991e-01 > > Final REFMAC refinement in P21 > Rfactor = 0.2391 > Rfree = 0.2674 > After multiple rounds of refinement the twinning information is: > Twin domains = 2 > Twin fractions = 0.5201, 0.4799 > > FINAL refinement PHENIX – P21 > Rwork = 0.1637 > Rfree = 0.1938 > Twin fraction = 0.5 for twin operator h, -k, -h-l > Ramachandran outliers = 0.1% > Rotamer outliers = 3.6% > C-beta outliers = 0 > > > C2221 > AIMLESS > Cut the data back to 2.25 for a Mn I/sd >2. > > Average unit cell: 74.68 247.4 130 90 90 90 > Overall InnerShell OuterShell > Low resolution limit 48.09 48.09 2.31 > High resolution limit 2.25 9.81 2.25 > > Rmerge (within I+/I-) 0.117 0.044 0.984 > Rmerge (all I+ and I-) 0.126 0.046 1.068 > Rmeas (within I+/I-) 0.136 0.051 1.145 > Rmeas (all I+ & I-) 0.135 0.050 1.147 > Rpim (within I+/I-) 0.069 0.026 0.577 > Rpim (all I+ & I-) 0.050 0.019 0.417 > Rmerge in top intensity bin 0.050 - - > Total number of observations 427886 5201 33337 > Total number unique 57553 788 4433 > Mean((I)/sd(I)) 11.4 32.6 2.0 > Mn(I) half-set correlation CC(1/2) 0.997 0.997 0.668 > Completeness 100.0 98.9 100.0 > Multiplicity 7.4 6.6 7.5 > > First round of refinement - REFMAC – C2221 > Rfactor = 0.2132 > Rfree = 0.2443 > > Final refinement round - PHENIX – C2221 > Rwork = 0.1853 > Rfree = 0.2330 > Ramachandran outliers = 0.1% > Rotamer outliers = 7.1% > C-beta outliers = 0 > > This email may be confidential and subject to legal privilege, it may > not reflect the views of the University of Canterbury, and it is not > guaranteed to be virus free. 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