Re: [ccp4bb]: thorium

[Manfred Buehner <buehner@biozentrum.uni-wuerzburg.de>]

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On Thu, 17 Oct 2002, Marie-Laure Chesne wrote:

> Dear crystallographers,
> 
> I search informations about tests with thorium as a derivative agent
> for protein crystallography.
> It seems that TPA have already be tried, but i can't find any reference
> about this.
> Does anyone know more about this trial and do you know exactly why
> thorium
> is not used finally as a derivative agent ?

Ages ago we tried thorium nitrate on several protein
crystals, but never had any usable results. Due to its
chemistry ("earth" metal-like, similar to Ca and the rare
earths etc) it is not naturally binding well to proteins.

And maybe it is not the best idea to put a source of
ionizing radiation into your crystal, even a weak one.

We got it from Merck at the time, but they seem to have it
discontinued, same as Alfa / Johnson Matthey. No idea what
the reason could be.

Manfred

----------------------------------------------------------
 Dr. Manfred Buehner             Phone:  +49-931-888-4100
 Physiologische Chemie           FAX:    +49-931-888-4150
 Theodor-Boveri-Institut fuer Biowissenschaften
 Biozentrum der Universitaet Wuerzburg
 Am Hubland,  D-97074 WUERZBURG,  Germany
 Email:  buehner@biozentrum.uni-wuerzburg.de
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