Hi Gabriel - If the crystal contacts really are all the same, it sounds to me like your MR program may have just placed the monomers in different but equivalent symmetry-related positions between the two structures. Try moving the outlying monomers to the symmetrically related positions that would complete the tetramer. The PISA server may help with this. You could also do this from within COOT (Extensions > PISA... > PISA Assemblies...).
Cheers, Jared -- Jared Sampson Xiangpeng Kong Lab NYU Langone Medical Center 550 First Avenue New York, NY 10016 212-263-7898 http://kong.med.nyu.edu/ On Jan 22, 2014, at 3:50 PM, Gabriel Moreno <gabe.li...@gmail.com> wrote: > Dear CCP4 Contributors, > > I have a bit of a mystery: > > Two co-crystals that I picked up from the same grid tray (the two conditions > vary slightly in %PEG and [salt], both indexed as P1 (apo structure normally > crystallizes in P3221). One dataset was indexed, integrated and scaled with > HKL2000. The other was processed with MOSFILM (could not process in HKL2000). > Downstream processing for both sets was done exactly the same in PHENIX. > Though both asymmetric units contain two complete tetramers, the interesting > thing is that the configuration of monomers is different between the > solutions. One contains one complete tetramer, one trimer (with a void where > the fourth monomer would be), and one monomer on off on its own. The > asymmetric unit of the other dataset solution also contains a complete > tetramer, but then has two dimers. Close analysis of contacts between > symmetrically related molecules reveals that the crystal packing is exactly > the same between the two solutions from the two datasets. Also, the Rwork and > Rfree for both models are 0.18 and 0.20. Other quality indices are also > comparable between the two sets. > > Here's my question: Does this phenomenon reveal anything important, or is > this type of thing just seen sometimes with P1 solutions from crystals of the > same protein and condition (more or less). > > I hope I have been clear. > > Thanks! > > Gabriel ------------------------------------------------------------ This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain information that is proprietary, confidential, and exempt from disclosure under applicable law. Any unauthorized review, use, disclosure, or distribution is prohibited. If you have received this email in error please notify the sender by return email and delete the original message. Please note, the recipient should check this email and any attachments for the presence of viruses. The organization accepts no liability for any damage caused by any virus transmitted by this email. =================================
