Hi everyone,

I have been issues with a particular protein. I have been close for a while, but yet so far. 

Rather than going from a clear drop to crystal, my protein first undergoes phase separation (large oily drops) in which one phase contains most, if not all, of the protein. This phase separation occurs within a day of preparing the drop. A day after phase separation the oily phase is now a large disordered crystalline mass which does not diffract very well. I have tried changing buffer concentrations, precipitant amounts, ionic strengths and pH and in all cases this phenomenon is observed. I even screened protein concentrations to see if reducing protein concentration would prevent the phase separation.

Is there any way to bypass this phase separation, which I think prevents me from obtaining nice crystals. Should I try detergents, chaotropes, or other additives?

Thanks in advance.

Timur

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F. Timur Senguen, Ph.D.

Postdoctoral Research Fellow

Boston Biomedical Research Institute

64 Grove Street,
Watertown,
MA 02472 USA