Dear Andre,
you could try with the protocol described in the following paper
Acta Crystallogr D Biol Crystallogr. 2013 69,920-3.
Using high-throughput in situ plate screening to evaluate the effect of
dehydration on protein crystals.
Douangamath A, Aller P, Lukacik P, Sanchez-Weatherby J, Moraes I,
Brandao-Neto J.
It gives very good results with membrane proteins where the water
content is high.
Danilo
On Tue, 29 Oct 2013 08:18:21 -0700, Andre Godoy
<[log in to unmask]> wrote:
> Dear all
>
> I'm trying to solve a beautiful large crystal that, unfortunately,
> doesn't go further than 5 A resolution. I believe that in this case,
> the lack of resolution is due the high solvent content (about 66%).
> Therefore, my next strategy should be the dehydratation. Yet, I never
> (sucessfully) did that. I read different approachs, were people
> equilibrate crystals in dehydratation solution for days, or do more
> than 20 steps, or add solvents. Since i never had sucess in my
> trials,
> I was thinking that someone can suggest a protocol (should I remove
> all salt?, should I keep the additive concentration?, how much
> precipitant should I add? how many steps?).
>
> crystal condition: 23% PEG 3350, 0.2M NaCl, 0.1M Tris pH 8.5, 3%
> galactose (orthorhombic crystals, with about 0.6 x 0.6 mm)
>
> all the best,
>
> Andre Godoy
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