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Re: Freezing



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Dear Swami,

Yet another idea for freezing:

1. If your crystals are large enough, take a small loop and fish the
   crystal such that the crystal is sitting on top of loop and  _NO_
   solution sticks to it anymore. I had such cases where I didn't need
   any cryoprotectant at all simply because there is not water to freeze. 

2. I just realized that very high salt concentrations also act as cryo-
   protectants. I had saturated ammonium sulfate as precipitation agent
   and for this crystallization condition I did not need any
   cryoprotectant.
   I do not know whether NaCl can be used in the same way, nor do I know
   whether your crystals would stand a condition such as staturated NaCl
   ... but you can give it a try.


Good luck,

Pete
___________________________________________________________________________

Peter Burkhard
Abteilung Strukturbiologie
Klingelbergstr. 70
CH-4056 BASEL, Switzerland

Phone:	++41 61 267 20 91
Fax:	++41 61 267 21 09
E-mail:	burkhardp@ubaclu.unibas.ch

> On Thu, 23 Sep 1999, Kunchithapadam Swaminathan wrote:

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> 
> Dear :
> 
> I have got a crystal and the condition is:
> 
> 100 mM Tris-HCl, pH 7.5
> 150 mM Nacl
> 20 mM  Ca Cl2
> 
> (The crystal dissolves in conventional method of freezing, time course
> transfer in artificial mother liquor + 5%, 10%, 15%, 20%, 25% glycerol, MPD,
> PEG400).  I am looking for suggestions/advice for freezing crystals grown in
> pure salt environment.  Any tips?
> 
> With regards,
> Swami
> 
>   ****************************************************************************
>   Dr. Kunchithapadam Swaminathan		Phone: 	(65) 873 2173 (H)
>   Institute of Molecular Agrobiology			(65) 872 7408 (W)
>   The National University of Singapore		Fax:	(65) 872 7007 (W)
>   1 Research Link, Singapore 117604		Email:	nathan@ima.org.sg
> 
>   Web:	www.ima.org.sg/research/struct_bio/struct_bio.html
>   ****************************************************************************
> 
>