Hi All, I have set up initial screen in hanging drop trays with a protein of theoritical pI of 8.5. The protein is in acetate buffer 10mM, KCl 100mM and 2% glycerol pH 5 . In 85-90% of the conditions I see granular precipitate in 1 day. I tried to open the coverslip, and touch few drops, They had a skin layer and the granular looking thing are part of the skin. The protein was set up at 10 and 5 mg/ml concentration. Is this normal?
I have tried to change the protein buffer to Hepes at pH 7 with other constituents same,and tried to set up few screen trays. I cant see granular precipitate again. The precipitates look light brown and amorphous in nature. Is Na acetate forming some granular precipitate instead of protein? Kindly suggest me ways to move forwards. Thanks in advance Anita
