Dear Ursula, just a stupid question: did you try freezing a crystal? There are quite a few crystal structures in the PDB with (a) bound Tris molecule(s), so quite some crystals were not destroyed by a pH shock during freezing. If you tried freezing and saw no/bad diffraction, you should try to take some shots at room temperature to find out whether the diffraction is destroyed by the freezing, or whether your crystal diffracts just badly from the very beginning. There are sleeves you can put over the loop with your crystal to prevent the crystal from drying out.
Good luck, Herman Von: CCP4 bulletin board [mailto:[email protected]] Im Auftrag von Ursula Schulze-Gahmen Gesendet: Freitag, 12. Juni 2015 22:47 An: [email protected] Betreff: [ccp4bb] Tris buffer in cryo protectant 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. Ursula -- Ursula Schulze-Gahmen, Ph.D. Project Scientist UC Berkeley, QB3 360 Stanley Hall #3220 Berkeley, CA 94720-3220 (510) 643 9491
