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:[log in to unmask]] On Behalf Of
> R
>> Conners, Biochemistry
>> Sent: 17 February 2011 17:03
>> To: [log in to unmask]
>> 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
>> [log in to unmask]
>> 0117 3312149
>
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