Re: [ccp4bb] Off topic: ask about cryoprotectant selection using lithium sulfate as precipitant for crystal growth

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Subject: Off topic: ask about cryoprotectant selection using lithium sulfate as precipitant for crystal growth
From: wu donghui wdh0972 {- at -} GMAIL {- dot -} COM
Date: 2008-02-26

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Subject: Re: Off topic: ask about cryoprotectant selection using lithium sulfate as precipitant for crystal growth
From: wu donghui wdh0972 {- at -} GMAIL {- dot -} COM
Date: 2008-02-26

Subject: Re: Off topic: ask about cryoprotectant selection using lithium sulfate as precipitant for crystal growth
From: Juergen Bosch jbosch {- at -} U {- dot -} WASHINGTON {- dot -} EDU
Date: 2008-02-26

Have you tried the various oils ?
As a last resort Greek olive oil if paratone and others fail.
How about sugars ?
Stay away from propanol, your crystals will start floating through your
wells with very rapid movements. I once had a 30% 2-propanol crystal
condition and mounting crystals only worked somehow in the cold room and
with lots of luck.

Jürgen

wu donghui wrote:

> Dear all,
>
> Recently, I got a crystallization condition as 0.1 M Bis tris ph 6.5,
> 1.3M lithium sulfate, 0.1M NaCl, the shape of crystals is needle
> cluster, very difficult to grow bigger, microseeding does not work,
> then I tried macroseeding, and found crystal can grow bigger and rod
> like. However as for the cryoprotectant, crystal will dissolve in
> glycerol, ethylene glycol, MPD and PEG, even in the very low
> concentration about 5%. I found my crystal can grow under the additive
> 2-propanol in addition to the above mentioned crystallization
> condition. I also noticed that Hampton cryoprotectant kit has the
> 2-propanol as cryoprotectant. I want to know if anyone have ever used
> 2-propanol as the cryoprotectant and what effect it might be. By the
> way Hampton also mention lithium sulfate can be used as
> cryoprotectant, the recommended maxium concentration is 2M, I tried
> and found ice ring is severe and it is very easily to form lithium
> sulfate salt crystal at this high concentration, I also tried sodium
> malonate, the diffraction gave me few spots, resolution is only about
> 6--7 angstrom.
>
> Does anyone encounter such problem by lithium sulfate?
>
>
> Welcome to any replies. Thanks a lot in advance.
>
> Donghui

--
Jürgen Bosch
University of Washington
Dept. of Biochemistry, K-426
1705 NE Pacific Street
Seattle, WA 98195
Box 357742
Phone: +1-206-616-4510
FAX: +1-206-685-7002
Web: http://faculty.washington.edu/jbosch

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