Different suggestion:
I assume you don't have problems obtaining crystals, so I'd setup a 24
or 96 well plate with your preferred condition then add to each row or
column a different know cryo at low concentration e.g. 1-10%. Then
under the conditions in which you still get crystals in the presence
of the cryo I would soak the crystals in a proper cryo condition for
this particular additive and flash freeze the crystal in liquid
nitrogen and not in the stream.
You seem to be very close to cracking your problem, don't give up and
try a lot of things. As someone mentioned already do flash annealing
and you can do this also with the liquid nitrogen by lifting your
crystal out of the bath before plunging it back in - sure you're
missing a data point there what would the diffraction have been if I
had not done this. In my hands I ALWAYS try flash annealing with every
crystal - you can only learn, there's nothing to loose. The question
is only what do you call a bad diffracting crystal 3Å ? 4 Å 6 Å?
Here's a more recent example July 2009
http://web.mac.com/bosch_lab/jbosch/Labfun.html#4
The crystals are tiny ~20x20x60 (not really visible in the image on
the web) and before flash annealing diffracted to maybe 5A. I brought
this data set home with 2.2Å longest cell 220 Å (shot at SSRl 9-2)
Good luck,
Jürgen
On Oct 7, 2009, at 4:54 PM, ycheng wrote:
-
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/
