Hmmm…not enough information but I am wondering about the EDTA plus Ca business….the Ca++ ions are forming a strong chelate with the EDTA, so
depending on your molar ratios either the free Ca ions would be consumed by EDTA or the EDTA by Ca …(?) – any variance in ratio here might prove troublesome. BR From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of dusky dew Sent: Montag, 14. Juli 2014 13:44 To: [email protected] Subject: [ccp4bb] cannot reproduce crystals 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!
