On Mon, 07 Jan 2013 18:30:32 +0100, Joy <[log in to unmask]> wrote:
> Dear Bryan,
>
>
> Thank you very much for the comments, I have tried glycerol and it did
> affect the resolution, at the same time, through reading former posts, I
> find that sucrose might not be a good choice for crystals grown in salt,
> I will definitely try adding glycerol stepwise, but at the same time,
Glycerol is a solubilizer. A step wise approach will work only if as you
increase the glycerol concentration you also increase the precipitant
concentration. Be careful of salt crystals appearing as you take this path.
> I am wondering if high conc. ammonium phosphate could be used as
> cryoprotectant, if so, I would be able to achieve dehydration and cryo
> at the same time.
All salts will prevent ice formation at high concentration, but some reach
the crystallization point
before. There is also the possibility of making a salt mixture by adding
for example
ammonium formate, an excellent cryosalt.
If you try the experiment and let the BB know the result.
Enrico.
>
>
> From: Prince, D Bryan [mailto:[log in to unmask]]
> Sent: 2013年1月3日 17:17
> To: Joy
> Subject: RE: [ccp4bb] Ammonium phosphate as cryoprotectant
>
>
> Dear Joy,
>
>
> I do not believe that ammonium dibasic phosphate will make a good
> cryosalt. I would recommend a lithium cryosalt (formate, acetate or
> sulfate) or glycerol if you really need to stay with the phosphate.
>
>
> Hope this helps!
>
>
> Bryan
>
>
> _____
>
> Confidentiality Notice: This message is private and may contain
> confidential and proprietary information. If you have received this
> message in error, please notify us and remove it from your system and
> note that you must not copy, distribute or take any action in reliance
> on it. Any unauthorized use or disclosure of the contents of this
> message is not permitted and may be unlawful.
>
>
> From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Joy
> Sent: Thursday, January 03, 2013 12:33 PM
> To: [log in to unmask]
> Subject: [ccp4bb] Ammonium phosphate as cryoprotectant
>
>
> Dear All,
>
>
> May I have your expert opinion on the following question: what is the
> minimum concentration of ammonium dibasic phosphate if I would like to
> use it as cryoprotectant?
>
>
> Happy New Year!
>
>
> Joy
>
--
Enrico A. Stura D.Phil. (Oxon) , Tel: 33 (0)1 69 08 4302 Office
Room 19, Bat.152, Tel: 33 (0)1 69 08 9449 Lab
LTMB, SIMOPRO, IBiTec-S, CE Saclay, 91191 Gif-sur-Yvette, FRANCE
http://www-dsv.cea.fr/en/institutes/institute-of-biology-and-technology-saclay-ibitec-s/unites-de-recherche/department-of-molecular-engineering-of-proteins-simopro/molecular-toxinology-and-biotechnology-laboratory-ltmb/crystallogenesis-e.-stura
http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html
e-mail: [log in to unmask] Fax: 33 (0)1 69 08 90 71
|