Re: [ccp4bb]: cryo-protect crystals grown in 35% dioxane

[Hong Zhang <zhang@chop.swmed.edu>]

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Hello, everyone,

I sincerely appreciate everybody who extended their help to me in this case.
I've tried most of the suggestions I received, and here is a breif summary:

1. Dioxan alone: crystals start melting after a few seconds in 35%-70%
dioxane (+little buffer and salt presented in protein buffer). I put a
crystal washed in 70% dioxane in the cold stream, and it looked a bit
cloudy. I didn't get to collect any frames due to a stupid mistake.

2. 35% dioxane + various glycerol:  crystal melted pretty fast.

3. 35% dioxane + 25% ethylene glycol or MPD: crystals start melting after
more than a few seconds. But I manage to freeze them before they gone bad.
These crystals are yet to be tested in the beam.

4. 35% dioxane + 25% PEG400: I am currently collecting data on this crystal!
The crystal is stable for up to 5min in this solution. A few second wash
provided good cryoprotection (no ice rings), but mosaicity is a quite high
(~1.2).

That's all!

Hong Zhang
Department of Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Dallas, Texas 75390-9038
Phone: 214-648-9299
Fax: 214-648-9099