We regularly use 1-2 mM Mn2+ in xtal set-ups. The problem we've
encountered is formation of the insoluble, brown-colored Mn(OH)2 in
more basic solutions, but we've also found that the Good buffers
(HEPES, EPPS, etc.) are less prone to the formation of the
precipitate, while Tris seems to promote its formation. That said,
I've had xtals that diffract very well, with bound Mn, come out of
drops containing the precipitate.
Good luck,
Arthur
Arthur Glasfeld
Department of Chemistry
Reed College
3203 SE Woodstock Blvd.
Portland, OR 97202
USA
On Apr 6, 2009, at 11:14 AM, Matthew Alan Bratkowski wrote:
> Hi.
>
> Does anyone have experience using solutions containing manganese as
> crystallization buffers (buffers, not screening well solutions)? The
> protein that I am working requires manganese for activity, and I
> have read
> reports of related proteins crystallizing in manganese buffers. I
> made a
> buffer containing 3 mM manganese, that initially had a black color
> then
> turned to deep purple, and later almost clear. After a few weeks, the
> buffer turned an orange color and contains dark manganese syrup on the
> bottom. Does anyone know how to prepare a manganese buffer that is
> stable
> enough to be used as a protein buffer for crystallization screens?
>
> Thanks,
> Matt
>
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