a most approapriate paper for the method that i described earlier is in the following paper. Follow the link
Optimum solubility (OS) screening: an efficient method to optimize buffer conditions for homogeneity and crystallization of proteins http://journals.iucr.org/d/issues/2004/09/00/dz5020/dz5020.pdf Padayatti PS On Thu, Apr 29, 2010 at 6:53 AM, Jhon Thomas <[email protected]> wrote: > Hello BB > > I am working with small protein-protein complex of Molecular weight 40kDa. > This protein expresses well and soluble in 20mM Tris-Cl pH-8.0 and 50mM of > KCl, could be concentrated upto 20mg per ml in this buffer. I have purifed > this protein with Ni-NTA resin and they are free from any contaminants. > Therefore, this protein have been directly used for the screening. I > started crystallisation screening with INDEX screen of hampton research and > some other lab made random screen. It precipitates immediately in the most > of the condition (85%) except those conditions where PEG and Jeffamine are > as precipitant with HEPES or Tris-Cl buffers above the pH value 7. > Another conditions where it doesnot precipiatate are 0.1M Tris-Bis pH-5.5 + > 3M NaCl , and 0.1M Na-Acetate pH-4.5 + 3M NaCl. This is a strange behaviour > of the protein complex. I would appreciate the suggestions in this concern. > What are the other possibilties, which can be explored through this > observation? Although I can proceed for the screening with the other > screens like PEG Screen or crystal screen or some other random screens, it > would be better to find out the root problem of the immediate precipiation > of the proteins in the crystallisation conditions. > > Thanks in advance > > Jhon > -- Pius S Padayatti Scientist, Polgenix, Inc. 11000 Cedar Ave, Suite 260 Cleveland, OH 44106 Phone: 216-658-4528 Fax: 216-658-4529
