Insoluble Protein

iwilson at iwilson at
Mon Oct 25 13:06:32 EST 1993

In article <18OCT199313510964 at>, xiong at (Zhongguo Xiong) writes:
> Dear Netters:
> I have recently encountered a insoluble recombinant protein and need all kinds
> of suggestions or comments I can get. I over-expressed a plant RNA viral
> protein (possible a RNA-depedent RNA polymerase protein) in E. coli. The
> protein formed an inclusion body in the bacteria. I had no problems in
> solublizing the protein with urea and the subsequent protein purification in
> the nickel column. Then I dialyzed the purified protein against a series of
> Urea buffers with decreasing concentrations of Urea (from 8M to 0). Inspite of
> the precaution, the protein still formed precipitates. I tried to resolublize
> the protein in 4 M urea and dit not see any protein in SDS PAGE gel.
> Are there any way to make the protein soluble in a non-denaturing condition?
> Any comments and suggestions are welcome.> 
> Z. Xiong

In our group someone experimented with adding Cu(II) ions - I don't have the 
details with me and I have also recently seen a paper on oxido-shufling with 
glutathione GSH + GSSG mixtures since disulphides were involved (see recent 
paper in Protein Engineering on galactosyltransferase.

Iain Wilson
Dyson Perrins Laboratory, University of Oxford iwilson at

More information about the Methods mailing list