Herojit khun,
To have good diffracting crystals you should determine optimal
crystallization conditions.
8% PEG 3350 is atypically low. Try to shift to higher PEG concentration.
This might involve adding some NaCL or other salt (Salting-in/salting out)
Once you have better crystallization conditions you need to choose
cryo-conditions that
do not melt your crystals. (Glycerol melts crystals but it can be counter
balanced by
other componets that have the opposite effect)
145. Vera L., Stura E.A. (2014) Strategies for protein
cryocrystallography. Crystal Growth & Design, 14: 427-435.
http://pubs.acs.org/doi/full/10.1021/cg301531f
or:
149 Ciccone L., Vera L., Tepshi L., Rosalia L., Rossello A. & Stura E.A.
(2015) Multicomponent mixtures for cryoprotection and ligand
solubilization. Biotechnology Reports 7:120—127.
http://dx.doi.org/10.1016/j.btre.2015.05.008
Enrico.
On Fri, 25 Mar 2016 11:01:16 +0100, Herojit khun <[log in to unmask]>
wrote:
> Hi all,
>
>
>
> Condition of a rod crystal contains 8% PEG 3350, Tris 50mM pH 7.5, 100mM
> Na2
> SO4. Buffer (Protein) is tris 50mM, NaCl 50mM, ph 8.5. Most of the
> crystal diffracts upto 7 A only with Ice rings (without cryoprotectant).
> Crystals were grown in two weeks.
>
>
>
> With most of the cryoprotectants including 15% Glycerol(even lower %),
> the
> crystals are unstable, starts melting.
>
>
>
> Additive screening, changing of parameters of condition like pH,
> temperature, salt concentration did not work. Some crystals grows with
> 12%
> PEG 3350, but still it behaves the same.
>
>
>
> Kindly suggest to improve crystal quality, and cryoprotectant.
>
>
>
> -- Regards
>
> *KHUNDRAKPAM HEROJIT *
> NATIONAL INSTITUTE OF IMMUNOLOGY (*NII*)
> NEW DELHI, INDIA. 110067
> NATIONAL INSTITUTE OF IMMUNOLOGY (*NII*)
> NEW DELHI, INDIA. 110067
--
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
e-mail: [log in to unmask] Fax: 33 (0)1 69 08 90 71
Proxima-2A, Soleil Synchrotron. Tel: 33 (0)1 69 35 8180 Beamline
http://scholar.google.com/citations?hl=en&user=Kvm06WIoPAsC&pagesize=100&sortby=pubdate
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