[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Freezing

***  For details on how to be removed from this list visit the  ***
***    CCP4 home page http://www.dl.ac.uk/CCP/CCP4/main.html    ***

Dear Swami,

Rather than adding glycerol, etc to the mother liquor, prepare the
cryoprotectant to have the original concentration of precipitant. When
making your solutions, replace water in the recipe with glycerol. Glycerol,
ethylene glycol , etc.  tend to solubilize protein; often even higher
concentrations of precipitant are needed to avoid redissolving.

I had a crystal (ppt: PEG 4000) which did not tolerate even the slightest
amount of glycerol without cracking. But when I added a small (1%) amount
of glycerol to the crystallization conditions, I was able to cryoprotect by
transferring the crystal directly to the cryoprotectant (15% glycerol). The
crystal structure has what looks to be a bound glycerol.


Lisa Edberg (205)934-1611 FAX:(205)934-0480
Center for Macromol. Cryst., Univ. Alabama-Birmingham
"Mathematics is a way to see structures that are there-
all ready to help you if only you can see them." Gerard Bricogne