On Mon, 2011-11-07 at 05:19 +0000, Sam Arnosti wrote:
> Hi everyone
>
> I have a protein that is extraordinarily stable at PH=3.0 or even 2.0.
>
> I want to crystallize it in the low PH and compare the differences between the crystals in regular PH and low PH.
>
> I was wondering how people set up the boxes in low PH, as usual buffers are mostly less acidic.
>
> Regards
>
> Sam
Not clear if you already have crystals at "regular pH", but if you do,
you may consider direct transfer to lower pH. Of course, crystals may
dissolve, which you could possibly prevent by cross-linking with
glutaraldehyde. Three caveats:
a) If lattice is incompatible with lower pH, even with cross-linking the
resolution may sink to essentially useless levels
b) I have no idea if the cross-linking will not be disrupted at really
low pH, perhaps someone else can comment on that
c) the 3rd reviewer can always say that lattice forces could have
prevented a conformational change. But same goes for direct
crystallization at low pH (but caries less weight).
--
"I'd jump in myself, if I weren't so good at whistling."
Julian, King of Lemurs
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