Congratulations! I think you are now looking for additional crystallographic and non-crystallographic symmetry, because finding 40 particles in arbitrary positions and orientations is going to be brutal.
I wouldn’t take the cell and point group assignment from XDS at face value. Rather I think you should put XDS_ASCII.HKL through phenix.xtriage and POINTLESS in the CCP4 suite of programs. Both can be invoked from the command line. pointless HKLIN XDS_ASCII.HKL phenix.xtriage XDS_ASCII.HKL That handles the crystallographic symmetry part. Let us know how it turns out. It is also possible that there is extensive NCS, and if the space group assignment holds, I’d ask again about that. As Jacob Keller’s response suggests, most people are going to suggest that you lock down crystallographic symmetry before looking at NCS. Craig On Apr 26, 2017, at 2:34 PM, Jademilson Santos <jademilsonsan...@gmail.com<mailto:jademilsonsan...@gmail.com>> wrote: Greetings all, I am having trouble with a data set and would like to know if somebody can help. I'm working with a protein of approximately 50 kDa, which I have successfully crystallized. The crystals diffracted at a resolution of 3,65 angstroms and upon initial processing using XDS i obtained the following information: space group: P21 ISA = 33.3 cell unit: a=285.2, b=135.9, c= 287.5, α=90, β=117.5, γ=90 Matthews coefficient indicates that there are 40 molecules in the asymmetric unit I am currently running the program Phaser (Phenix) to determine the phase via molecular replacement with a model that has 49% homology and query coverage of 94% and the program is taking extremly long to finish. In this case in which there is an extremly high number of molecules in the asymmetric unit, is this actually possible? Does someone know how to work with these values and is there a specific strategy which i must follow? Regards Jademilson Celestino dos Santos Laboratory of Applied Structural Biology Department of Microbiology Institute of Biomedical Sciences University of São Paulo- USP
