Dear Sayan, If a subunit is correctly oriented, but the translation is incorrect, density for a ligand may still show up in the binding site of the protein. It might be that one of the 2-fold axes, you think is crystallographic, is in fact non crystallographic and a few Angstroms away from the crystallographic position.
What I would do: 1. Check the images: are there ice-rings or other artifacts that could cause scaling problems that would lead to high Rw/Rf values? In that case, there is not much you can do. 2. Compare the C2 and P22121 solutions: do they have the same overall crystal packing (CS+NCS), or are they different? Do they have the same Rw/Rf values? Can we learn anything from the differences in overall crystal packing? 3. Process, run MR and refine in P1. Do you get lower R-factors? If so, then run Zanuda to find out the real space group. Best, Herman Von: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> Im Auftrag von Sayan Saha Gesendet: Donnerstag, 28. Juli 2022 08:15 An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Regarding the correct space group identification Dear All, We have collected home-source X-ray intensity data for a protein at 2.6 Angstrom. The data can be processed in either C2 (a=120, b=80, c=85 and beta=115) or P222 (P22121, a=80, b=85, c=110). MR solution can be obtained in both the space groups. However, the solution can be refined with an Rw/Rf of 29/32% only. The protein is bound to a ligand (co-crystallization) for which a clear density can be observed. Any help and suggestion in this regard would be very helpful. With best regards, Sayan Saha. ________________________________ 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://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/
