dear petr, several phytochrome structures seem to represent mixed-state crystals. best, jon
-----Ursprüngliche Nachricht----- Von: CCP4 bulletin board [mailto:[email protected]] Im Auftrag von Petr Kolenko Gesendet: Dienstag, 11. Juli 2017 16:00 An: [email protected] Betreff: [ccp4bb] Inquiry - active and non-active state in alternatives Dear colleagues, We are working on a paper, where we want to discuss our crystal structure. We have determined structure of non-active state first (much easier). Than we tried to convert the protein into active state by soaking (direct crystallization not possible). We have observed more than a half of a protein chain in shifted location after soaking with respect to the original conformation as a 50% alternative. We believe that the alternative conformation corresponds to the active state and we are looking for any other possible support to our statement. My questions are: Has anyone else observed active and non-active state of a protein in single chain together as alternatives? Has anyone an idea how to search through the PDB for such cases? Simple going through all structures with alternatives does not seem to be reasonable. By the way, we are sure with the space group. Soaking may in some cases cause symmetry reduction, but if we process the data in lower symmetry, we see two chains with alternatives instead of one and this was not the only reason for our decision about the space group. We have also performed much more soaking experiments, but because of overall difficulty and instability of the chemicals, this was the best observation we ever had. Thanks for any suggestion! Best regards, Petr
