After extensive testing, I have found out that in most cases pH changes
during flash freezing does
not pose a problem. In some cases it can be beneficial. I encourage you
to try +/- 2 pH units
from your crystallization pH.
Sometimes a sub-optimal pH is chosen just because the crystals were
obtained the first time at that pH,
sometimes it is for strategic reasons, for example to prevent excessive
The best pH to obtain BIG crystals is not always the best pH to get the
Test various pH if you have enough crystals to do that.
On Fri, 12 Jun 2015 22:47:10 +0200, Ursula Schulze-Gahmen
<[log in to unmask]> wrote:
> Does anyone have experience with Tris buffer in cryo protectants? I would
> expect the pH of the cryosolution to increase a lot during flash freezing
> which could perhaps destroy the diffraction. I rarely use Tris for
> crystallization but the current protein really prefers Tris. I would
> appreciate any comments.
Enrico A. Stura D.Phil. (Oxon) , Tel: 33 (0)1 69 08 4302 Office
Room 19, Bat.152, Tel: 33 (0)1 69 08 9449 Lab
LTMB, SIMOPRO, IBiTec-S, CE Saclay, 91191 Gif-sur-Yvette, FRANCE
e-mail: [log in to unmask] Fax: 33 (0)1 69 08 90 71