Hi everyone,
We got crystals that grew in ~3.2M ammonium sulphate and some
tris-buffer at 18dgC. Unfortunately the crystals take a while to grow
(~4-5 weeks) and so far we only have 4-5 xtals.
I tried to freeze the crystals, but as soon as I broke though the skin
of the drop the ammonium sulphate started to crystallise. I got the
crystals out, froze them using sort of an artifical mother liquor with
sodium malonate as cryo and tested the diffraction. The freezing seems
to be OK and it is definitely a protein crystal. The crystal suffered
when the ammonium sulphate in the drop started to crystallise, but
didn't seem to deteriorate anymore in the cryo. Well the corners had
already more or less disappeared by the time I got them out of the drop...
Since we only have a few xtals at the moment and I can't try out a lot
of things, I was wondering if anyone has experienced and solved a
similar problem? My freezing attempt so far was in an airconditioned
room with 18dgC. I thought about higher humidity and temperature in the
room, and/or adding the cryo directly to the drop....
Any ideas are very much appreciated!
Sabine
------------------------------------------
Dr. Sabine Schneider
Ludwig-Maximilians-University
Department of Chemistry and Pharmacy
Butenandtstrasse 5-13, Building F
81377 Munich
Germany
Phone: +49 (0)89 2180 77846
Fax: +49 (0)89 2180 77756
http://www.carellgroup.de/
