Hi Peter,
If the crystals are brownish, then it may be crystals of Hexamine cobalt (III) chloride.
If you have the final dialysis buffer of the protein, setting up a crystallization trial with just the buffer may help you distinguish between salt and protein.
Hope this helps,
Wataru
On 2011/07/07, at 11:24, Peter Hsu wrote:
> Wanted to get an opinion. I set up a screen a while ago and got these very small cubic looking crystals 2-3 days later amidst a lot of precipitant. The condition was Natrix E1 (0.04M LiCl, 0.02M MgCl2, 0.04M Sodium Cacodylate pH5.5, 30% MPD, 0.02M Hexammine Cobalt (III) chloride). This protein's rather difficult to make, and I don't have a lot of it left frozen in the fridge after setting up the screens. Was wondering if anyone's ever observed salt crystals forming from this condition before? My protein's in 20mM HEPES pH7.5, 100mM NaCl, 5mM DTT.
>
> Thanks to all for any thoughts.
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