how much %PEG3350 ?
Try different additives such as glycerol, EG, MPD or smaller PEGs 200
or 400.
Try flash annealing
Try freezing directly in liquid nitrogen if you have previously frozen
your crystals in the stream
Try liquid annealing by dipping the frozen crystal into a new cryo
solution and re-freeze it.
The list can be continued quite a bit.
If you should find out that one of the cryo additives helps then try
to grow your crystals in the presence of those additives.
Good luck,
Jürgen
On Jan 26, 2010, at 10:42 AM, Zhiyi Wei wrote:
Dear all,
I got a problem with my crystals. I have two total different proteins
that both can be crystallized in the condition with PEG3350 and
Tacsimate
(although the concentrations are different) with different shapes. The
crystals look big and beautiful. However, when I test them in
synchrotron,
both of these two types of crystals showed poor diffractions. As
showed in
the attached diffraction image, the diffraction is up to ~4 A but
smear in
one direction while <8 A in the other direction. The interesting
thing is
that the diffraction pattern is similar for all crystals (from two
different
proteins) that I tested without exception although they belong to
different
space groups. So, I wonder whether these kind of pattern is caused by
Tacsimate (I don't know what it is) and how to rescue these
crystals. Any
suggestions or comments?
Thanks a lot!
Best,
Zhiyi
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Jürgen Bosch
Johns Hopkins Bloomberg School of Public Health
Department of Biochemistry & Molecular Biology
Johns Hopkins Malaria Research Institute
615 North Wolfe Street, W8708
Baltimore, MD 21205
Phone: +1-410-614-4742
Lab: +1-410-614-4894
Fax: +1-410-955-3655
http://web.mac.com/bosch_lab/
