Cooling will be extremely slow in the mitegen sheath - remember in
glass capillaries the crystal is right on the wall of the cap, stuck
on with a bit of mother liquor. In the mitegen system the crystal is
on a pin in the center of the sheath, so thermal contact with the
outside will be through the gas layer between it and the wall
(compare your double-pane energy-saving glass windows) or through
the base, up the pin, through the yellow plastic foil to your crystal.
Not to disourage you from trying, but you might want to use a stronger
cryoprotectant than usual.
eab
Colin Nave wrote:
Becky
Do you have the nitrogen stream co-linear with the capillaries, with the
specimen near the capillary end and therefore near the nitrogen stream
exit? This might help to minimise turbulence - though nowadays other
bits of kit fight to occupy this space.
Regards
Colin
-----Original Message-----
From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of
R
Conners, Biochemistry
Sent: 17 February 2011 17:03
To: [email protected]
Subject: [ccp4bb] Freezing crystals in a contained system
Dear all,
We are working on a Category 3 protein which must be contained so we
have
our crystals mounted in a loop and then covered with a plastic Mitegen
cover which is glued in place. We're currently collecting at room
temperature, but wondered if anyone has any experience of using a
contained
system at low temperatures? Any attempts I've had so far at freezing
through either the plastic or a glass capillary have resulted in
formation
of ice on the surface so it is not even possible to see the crystal to
centre it.
Best wishes,
Becky
-------------------------------------------------
Dr Becky Conners
School of Biochemistry
University of Bristol, UK
http://www.bris.ac.uk/biochemistry/brady
[email protected]
0117 3312149
