Hi Tom, Currently I am also working a protein which likes to be soluble aggregates. I am surprised to known that you manage to disrupt the aggregate to dimmer. So far I have made many truncations however without any success so far. I might try high salts and several detergents later. Does your protein interact with other proteins or nucleic acids in vivo? Maybe a group of residues which involve these in-vivo interactions contribute to the aggregation ---- it might be a group of charged residues. You can try to get the electronic potential map of your proteins to see whether there are highly charged pocket/site. The mutation of these residues possibly against the aggregation.
Kind regards, Wenhe Sent from my iPad > On 27 Feb, 2014, at 3:47 pm, Tom Wong <wangnan4...@yahoo.co.jp> wrote: > > > Hello everyone! > > I have run into a problem in a 55kD recombinant human protein crystallization > (expressed in E.Coil). The purity is pretty good. However, it behaves as high > oligomers in the buffer with 300mM NaCl and behaves as dimers with a little > high oligomers in the buffer with 2000mM (2M) NaCl. > I have already performed several screenings and tried several types of > buffer, salt or different pHs, etc. Only very small crystals could be > detected in the dimer drops. High oligomers seem could not be crystallized > under various of conditions. > > Has anyone ever met the same problem? Could anyone give me some suggestions? > > Thanks very much! > > > Cheers > > > --------------------------------------- > Tom Wong > Structural Lab > ---------------------------------------
