Set up your trays with N:1 ratio of protein:well sol'n, where N > 1, up to, say 5:1? That will tend to concentrate the protein in the drop above the original concentration.
JPK From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Mattiroli,Francesca Sent: Monday, February 16, 2015 11:23 PM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] how to reduce protein solubility Hi all, I am struggling with a protein complex that is too soluble. I have reached about 20 mg/ml but I still observe very little precipitation (clear drops in 90-95% of the tested conditions). The proteins are expressed in insect cells and going to higher concentration is not easily achievable. I have tried different buffer conditions (salt concentration and pH) and I am testing temperatures. I am at a loss with what to try next. Do you think PTMs (phosphorylation, acetylation) might be causing this? Any input on how to decrease solubility? Thank you very much in advance, Francesca
