Dear Simon, A long time ago, we have transferred crystals from a concentrated ammonium sulfate liquor to a PEG solution by first determining the equivalent PEG concentration and then essentially dunking the crystal in. It has been described in the following publication: J. Appl. Cryst. (1988). 21, 426-429
Best regards and good luck! Herman Schreuder -----Ursprüngliche Nachricht----- Von: CCP4 bulletin board [mailto:[EMAIL PROTECTED] Im Auftrag von Yue Li Gesendet: Donnerstag, 24. Mai 2007 20:25 An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] removal of sulfate ion from the active site Hi all, I have crystals of the apo enzyme growing from 1.7M ammonium sulfate condition. After soaking with 10mM ligand (substrate analog) which has a phosphate group, the ligand did not enter the active site of the enzyme because of the competition of sulfate ion and phosphate group. So I am wondering if anyone knows how to get rid of ammonium sulfate from crystal before soaking it with the ligand solution? Thanks a lot. Simon
