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Dear Ursula,
unless it is too long a list, maybe you could list the
cryo-protectants you have used so far? Did you try sugars (e.g.
glucose), or Na Malonate, or Butanediol (either 2,5 or 1,6, I don't
remember exactly)?
You could also increase the protein or NaCl concentration a little and
decrease the temperature to 10 degrees, say, for crystallisation, then
to 4 degrees to harvesting.
But first I would try as Jacob suggested, collect at room temperature
in a capillary. It's a very gentle treatment for crystals (except for
the X-rays ;-) ). When you transfer the crystal with a pipet and the
capillary, it is never exposed to air and you can work in the cold
room to stabilise the temperature.
Regards,
Tim
On 03/02/2015 07:49 PM, Ursula Schulze-Gahmen wrote:
> I know there was jut recently a discussion about cryoconditions
> for crystals, but I am still hoping for some new ideas for my
> crystals that grow from HEPES buffer pH 7.3, 0.2 M NaCl by slowly
> lowering the temperature from 20 to 4 degrees.
>
> These crystals are easy to grow but extremely sensitive to
> temperature change, and any of the usual cryo reagents tested so
> far simply dissolve the crystals. I am n ot sure how I could
> counteract the solubilizing effect of glycerol or ethylen glycol,
> since there is no precipitant concentration that I could increase
> to stabilize the crystals. Paratone didn't work either so far.
>
> Any other ideas for these low salt crystals?
>
> Ursula
>
- --
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen
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