My usual first approach to increasing crystal size is to decrease
precipitant and increase protein concentration, keeping the mixture in
the proper nucleation zone, but providing more protein for crystal
growth. Minimizing dust or particulates by filtration and centrifugation
of reagents and protein may help, by reducing nucleation sites in the
solution. Crystallization at a lower temperature may also result in
fewer, but larger crystals. Or you could try seeding.
Cheers,
--
------------------------------------------------------------------------
Roger S. Rowlett
Professor
Colgate University Presidential Scholar
Department of Chemistry
Colgate University
13 Oak Drive
Hamilton, NY 13346
tel: (315)-228-7245
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Walter Novak wrote:
> Hi Vince,
>
> There is a very nice paper by Monika Budayova-Spano in Acta Cryst 63D
> 2007 339-347. "A methodology and an instrument for the
> temperature-controlled optimization of crystal growth."
>
> Best,
> Wally
>
> On Sep 10, 2008, at 2:23 AM, Vincenzo Carbone wrote:
>
>> Dear all,
>>
>>
>>
>> I was wondering if anyone had some practical advice in regards to
>> increasing the size of a crystal. Currently my enzyme forms these
>> rather nice cubic and very sharp <0.1mm (in 25% peg 5000, 0.1M
>> ammonium sulphate, 0.1M Tris ph 7.0) crystals following optimisation
>> of the pH and precipitant concentrations of the initial screening
>> condition and by playing with various increasing levels of protein
>> concentration 20-60mg/ml.
>>
>>
>>
>> Has anyone had success with additive screens in increasing crystal
>> size and what were they?
>>
>>
>>
>> Any advice would be useful thanks
>>
>>
>>
>> Vince
>
>
> Walter R.P. Novak, Ph.D.
> Postdoctoral Fellow
> Rosenstiel Basic Medical Research Center
> Brandeis University
> 415 South St. MS 029
> Waltham, MA 02454-9110
> Phone: (781) 736-4944
> Fax: (781) 736-2405
>
>
>
>
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