Dear Sam, The first thing that would come to my mind would be ice rings, but since you said you don't have them, there must be another reason for the high Rs. Zanuda will give you back the space group you used for MR and maybe a higher symmetry space group, but the program cannot be used to confirm that the space group you assigned is correct. For that, you will have to run Phaser with all possible P2x2x2x permutations. I assume you have already done that. If not, that would be the second thing I would try. You could even use your rebuild model as a search model.
The next thing would be to look into the ligand you used. If the ligand has partial occupancy and induces some conformational changes in the protein, your crystal may contain proteins with a mixture of conformations, which may also give rise to higher Rfactors. Good luck, Herman Von: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> Im Auftrag von Sam Tang Gesendet: Donnerstag, 1. April 2021 14:28 An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] High Rs Dear all I have a dataset processed to 2.2 A, P212121, with no major issues identified by Xtriage (no tNCS, no twinning, no ice ring, good completeness). Phaser-MR gave a good solution except some loop regions are shifted. There is only 1 molecule in the ASU (and seemingly no more molecule can be accommodated). I fitted the displaced loops, and confirmed the space group by Zanuda, but the R-factors stuck at 0.34/0.41 range. What other aspects should I look into? Twin-refinement? (I am a bit reluctant to do so because neither Xtriage nor Pointless report it is twinned) I should also point out that the crystal was grown with its ligand but I cannot see good density for it. BRs Sam ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jiscmail.ac.uk%2Fcgi-bin%2FWA-JISC.exe%3FSUBED1%3DCCP4BB%26A%3D1&data=04%7C01%7CHerman.Schreuder%40SANOFI.COM%7C24d0d2227427449212e008d8f509b65b%7Caca3c8d6aa714e1aa10e03572fc58c0b%7C0%7C0%7C637528769783183293%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=%2BGUemqHp%2BwV8Seq84BJCNkej03RQGCwyZBrur66%2FRCQ%3D&reserved=0> ######################################################################## 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/
