? Spontaneous precip of alphahelix protein

John A. Newitt newitt at removeme.nih.gov
Fri Jun 25 12:12:45 EST 1999

In article <99Jun23.091553gmt+0100.19720 at fsk.ssi.dk>, tob at ssi.dk wrote:

> Hello
> I am currently working with a recombinant protein that has a tendency to
aggregate and precipitate spontaneously during purification. According to
the amino acid sequence it has a high alpha-helix content and a predicted
coil-coil structure. It is not a membrane protein. Any suggestions what to
add to the buffers to keep the protein soluble? I do not want to use
potentially harmful substances eg SDS or trifluoroethanol, a stabilizer of
the alpha-helical conformation. I appreciate any suggestions and references
that could be of help to solve my problem.

You might try looking back at the nuclear lamin literature (coiled-coil
IFs). If I remember correctly, they are only soluble in high concentrations
of urea at neutral pH, but when one uses a rather basic pH they are nicely


John A. Newitt, Ph.D.           |   <newitt at removeme.nih.gov>
National Institutes of Health   |   FAX: 301-402-0387
Bethesda, Maryland  USA         |   

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