Hi, since you used Xtriage to detect twinning it appears to me you are also in the Phenix ecosystem and so you can give a phenix.refine try to see what happens (make sure to tell it about twining, it won't use it by default!). Note, you can't use R factors to meaningfully compare refinements (twin vs nontwin). Good luck! Pavel
On Tue, May 27, 2025 at 10:01 AM Martin Malý <martin.maly...@email.cz> wrote: > Dear Janani, > > There has been recently a significant development in twin refinement > algorithms in Servalcat. Could you try this program and let us know if > it helps? > You can find Servalcat in i2 in the most recent version of CCP4. You can > also run it in terminal/CCP4Console: > servalcat refine_xtal_norefmac --hklin data.mtz --model model.pdb -s > xray --labin I,IMEAN,FreeR_flag --twin > (Assuming your MTZ data file has columns I,IMEAN,FreeR_flag.) > > Full list of options: > servalcat refine_xtal_norefmac -h > > Please feel free to ask if anything was not clear. > Cheers, > Martin > > > On 27/05/2025 07:00, Janani Ganesh wrote: > > Hello, > > > > I recently collected diffraction data and I was able to do the data > processing upto 1.88 Å. I observed the R-merge remained the same throughout > the resolution bins. I could solve the structure using Phaser in the space > group P32 2 1 (no. 154). But when I refined the structure the R-factors > remained ~ 35 % even after several cycles of refinement and model building. > > > > Then I looked for twinning in my data using Xtriage, Detwin, Pointless, > etc which indicated twining. Subsequently, I started twin refinement with > Refmac using twin law (-h, -k, l). The R-factors came down to ~25%. > However, the B-factors refined to 0.5 for all the atoms. I tried redoing > the data processing at lower symmetry space groups, P3, P31, P32, followed > by twin refinement but the issue with the B-factors persisted. > > > > I would appreciate any suggestions and advice towards resolving this > problem. > > > > Regards, > > Janani Ganesh > > > > ######################################################################## > > > > 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/ > > ######################################################################## > > 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/ > ######################################################################## 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/
