With that translation (x,1/2,1/2) lots of your reflections with k and l Odd will be relatively weak and those zones usually have higher r factors. Look at the plots of reflection zones in hklview and you will probably notice weak and strong zones.
The translation will make selecting the soacegroup a bit tricky but if you ran molrep and tested all spacegroups in the pointgroup Thst usually clearly suggests the right one. On Wed, 29 May 2024 at 15:05, Esko Oksanen < 0000533d495de740-dmarc-requ...@jiscmail.ac.uk> wrote: > Hi Cat, > > If your pseudo-centering actually leads to significant change in your > cumulative intensity distribution, you might have a convincing explanation > as to why the R-values would remain on the high side. I had a pseudo-body > centered case a long time ago (https://doi.org/10.1107/s0907444906031519) > and there the R-values remained a lot higher. > > HTH, > Esko > > On 29 May 2024, at 15:48, Catherine Back < > 0000d42dc456258a-dmarc-requ...@jiscmail.ac.uk> wrote: > > Hi, > > I have collected data for a protein which solved easily to 1.6 Å using MR. > However, during data analysis and refinement it clearly has translational > NCS. According to Xtriage on Phenix: > Frac. coord.: 0.072, -0.498, 0.5 > Distance to origin: 68.798 > Height relative to origin: 51.479% > p-value (height): 5.577e-05 > > Wilson value and L-test suggests no twinning. > > It solved using Molrep in ccp4i2. P2 21 21. All stats look good, but even > after refinement (not fully and completely finalised yet) R= 0.24 and > Rfree=0.27. Also, it appears the 2 molecules in the AU have swapped a helix > with their respective symmetry partners. I'm pretty sure I now have the > correct space group, and tried various others with much less success. > > > 1. Will these Rfactors be 'good'/low enough to publish for a dataset > at 1.6Å? > 2. Should I be doing anything else during structure solving to > alleviate the effects of tNCS? (I did try using Phaser to solve the > structure, but the stats were much worse and even though 'tNCS is present > correction factors were not applied'. I'm not sure why. > > > Many thanks, > Cat > > Dr Catherine R. Back (she/her) > Senior Post-doctoral Research Associate > School of Biochemistry > University of Bristol > UK > > > > > ------------------------------ > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 > > > > ------------------------------ > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 > ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
