Hi Raymond,
When I have spherulites, the first thing I do is to screen the pH (first in 0.5 units, and then screen a finer grid around the most promising conditions). You can go from spherulites to stars, needles or crystals just by changing your pH. Try a selection of 2 or 3 different buffers. You might need to optimise the concentration of your precipitant.
Are the spherulites solid, gelly or just some phase separation blobs?
With PEG, I would screen different molecular weight PEGs (take into account that the solubility is different and so the final concentration to be used should also be different if you use PEG 4K or PEG 10K).
I agree with Fred that additives can make the difference, not only the typical additives screens but also detergents.
Finally (it should be read, when you are desperate), you can also change the temperature.
Good luck.
Ciao,
Joao M. Dias
| "Fred. Vellieux"
<[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED] 09/06/2006 09:12 AM |
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On Tue, 5 Sep 2006 [EMAIL PROTECTED] wrote:
> Hi all,
>
> I have now progressed from phase separation to growing many nice
> spherulites, after many months of trying to crystallize some RNA-protein
> complexes. Has anybody out there been able to turn water into wine?
>
> If you have had any experience of successfully changing spherulites
> into single crystals with PEG, MPD, HD etc, then I would really like to
> hear about your success story.
>
> Any practical suggestions or tips are welcome?
>
> Cheers,
>
> Ray
>
> [EMAIL PROTECTED]
Hi,
Have you tried to see if your spherulites diffract? Sometimes the external
appearance hides well the wealth inside (speaking from experience, with
ugly looking spherulite like crystals that diffract to high resolution).
Also, you could take the condition(s) that give rise to the
"nicest" spherulite and use all the additives that are on the market to
see if anything comes out.
Fred.
--
s-mail: F.M.D. Vellieux (B.Sc., Ph.D.)
Institut de Biologie Structurale J.-P. Ebel CEA CNRS UJF
41 rue Jules Horowitz
38027 Grenoble Cedex 01
France
Tel: (+33) (0) 438789605
Fax: (+33) (0) 438785494
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