Hi, you changed something, and although it seems very small a change, this can make a difference between crystals and non-crystals. And removing the His-Tag is not a small change, since it influences the net charge.
The first thing to try is micro and macro-seeding. If they don't work, you may need to screen again. Best, Tim On 07/14/2014 01:44 PM, dusky dew wrote: > Dear all, > I am trying to reproduce some protein crystals. The protein I am getting > after cutting the his tag is very pure. I am using the reported protein > concentration. The cofactor and EDTA needs to be added externally. The > condition has calcium acetate, peg 4k and sodium acetate buffer. > Unfortunately I am getting oil separation and light ppt. I have no clue > what is wrong. Please help! > -- Dr Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A
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