Dear Appu, What is your problem? To me this crystal packing looks completely normal. If you look for tetramers in space groups with 422 symmetry I am sure you will find examples with a similar packing.
Best, Herman Von: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] Im Auftrag von Appu kumar Gesendet: Dienstag, 15. Juli 2014 00:57 An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Weired Crystal packing Dear All, I need your valuable suggestion in defining the arrangement of tetrameric protein in crystal upon symmetry mates information. I have attached a ppt for your evaluation. The monomer protein is composed of two domain (Domain 1 and Domain 2). In space group I422, the arrangement of tetramer upon symmetry mate information look weired because there are two kind of crystal contacts. The tetramer1 form crystal contact with tetramer2 through domain1 but on other side tetramer1 form crystal contact with tetramer3 through domain 2. Things will be clear if you will have look at the attached ppt. Therefore I request you to please look at the attached ppt. I have looked at the crystal packing in many tetrameric proteins which are either arranged in head to head or tail to tail in crystal but not in both head to head and tail to tail contacts in same crystal. Is this kind of crystal packing is possible? I need your valuable suggestion. Crystal is solved as monomer which upon symmetry mate information gives correct tetramer.
