Hi Ed,
good question. I have found that you have a good 30 seconds to remove
the surrounding liquid - so while you have to do it fast you have enough
time that it doesn't need a robot and even a malcoordinate such as
myself can do it. I'm afraid that I have no estimate for how often
diffraction is lost this way.... more info here
http://scripts.iucr.org/cgi-bin/paper?S0907444911031210
I started looking at this when doing dehydration experiments where it
has long been observed that you can directly cool the crystals after
dehydration - I have a feeling that 'over drying' a crystal leads to a
complete loss of lattice order - I have no evidence for this but all
systems that we have looked at that benefit from dehydration, or not,
come to quite a sharp cutoff where suddenly there is no more
diffraction, one can often recover diffraction by rehydration. This
could of course be due to too high a concentration of mother liquor but
quite often it occurs at relative humidity values Cheers, Matt.
On 2013-05-23 15:32, Ed Pozharski wrote:
Matt,
with this technique, how do you prevent crystal from drying up (other
than "doing it fast")? I know Thorne's group does this trick under
oil.
If you take no extra precautions, do you have an estimate of how
often
diffraction is destroyed by this?
On the other hand, it's quite possible that what destroys resolution
when crystals dry up is increase in concentration of non-volatile
mother
liquor components, which shouldn't be happening here to the same
degree.
Cheers,
Ed.
On Thu, 2013-05-23 at 14:38 +0200, Matthew BOWLER wrote:
Hi Faisal,
if your solvent channels are smaller than 40A in the largest
dimension
(most are) you can use a mesh loop to pick up the crystal and then
wick
away all of the mother liquor. You can then flash cool your crystal
without having to transfer the crystal to another solution. Good
luck,
Matt
--
Matthew Bowler
Synchrotron Science Group
European Molecular Biology Laboratory
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38042 Grenoble Cedex 9
France
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