Dear Jobi,
the paper of Heras and Martin 'Post-crystallization treatments for improving
diffraction quality of protein crystals' is really helpful.
Additionally, if you have lysines have you tried reductive methylation?
Good luck,
e
On Wed, April 13, 2011 12:34, Bingfa Sun wrote:
> Dear Jobi,
>
> For a crystal which is big in size(0.2-0.3mm is pretty big) while diffract
> poorly, dehydration (increase concentration of the precipitant slowly) is
> a good choice to improve diffraction, especially for those tends to crack
> during cryo.
>
> Also those regular optimization approaches: Additive screen etc. Sometimes
> cleave the tag or change it to another end will work.
>
> Cheers,
>
> Bingfa
>
>
>
> 发件人: [log in to unmask] [mailto:[log in to unmask]] 代表
> Jobichen Chacko
> 发送时间: 2011年4月13日 17:44
> 收件人: [log in to unmask]
> 主题: [ccp4bb] Crystal Optimization
>
>
>
> Dear All,
>
> We got crystals for a 35 KDa protein with 323aa including His tag and
> linker. It was originally crystallized in 0.1M BisTris Propane pH:6.5,
> 0.2M Potassium thiocyanate and 20% PEG 3350. Later we managed to obtain
> crystals with 0.1M BisTris pH:6.5, 0.2M Potassium thiocyanate and 20% PEG
> 3350 as well. Crystals are 3 dimensional in shape and 0.2-0.3mm long.
> Maximum resolution obtained till now is 5.8Å. Tried various cryo
> conditions like Oil, glycerol, salt and sugars. However, the resolution
> hasn't improved. The crystal tends to break in the presence of glycerol.
>
> Kindly give your suggestions to improve the resolution.
>
> Thanks.
>
> Jobi
>
>
>
>
--
**************************************************
Eirini Gkougkoulia
Department for Structural and Computational Biology
Max F. Perutz Laboratories
University of Vienna
Campus Vienna Biocenter 5
A-1030 Vienna
Austria
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