Ji,
probably the oil doesn't work and the glycerol gets you into problems
with phase separation in 2.5 M AmS
I recommend sucrose or other sugars with AmS - 20-22% (w/vol) should
do and you get no phase separation
At the same time you may need to increase the AmS considerably - often
the protein solubility in AmS increases significantly in the presence
of cosolvents.
I have previously had success with crystals grown in 1.9 M AmS, that
were cryoprotected by gradual transfer to 2.6 M AmS/20% sucrose. The
drops were then equilibrated against 3.5M AmS for a couple of hours
(dehydration) - without the final step in place (dehydration) the
crystal diffraction would be anisotropic at 3.5 Å resolution rather
than isotropic at 2.7 Å which was also the full potential revealed
from capillary-mounted crystals.
Poul
On 24/06/2008, at 02.14, Ji lee wrote:
Dear,
I have a crystal diffracted anisotrophically. I tested with a few
different cryo conditions like oil, glycerol in different
concentration to get a better data but these conditions didn't help
any.
Using capillary method improved the diffraction (isotrophic) but the
crystal couldn't survive during the data collection.
Is there any methods or cryo conditions I can use to improve my
diffraction data?
This crystal grew in 2.5M Ammonium Sulfate.
Thank you so much.
Ji
