I have been attempting to obtain a protein crystal of my protein for just over 2 years at this point. We have attempted removing the tag, binding the protein to its ligand, removing as much salt as possible (crashes at at too low a salt concentration)--this lead us to try reverse vapor diffusion--seeding, additive trays, optimization around the conditions an ortholog of one of the domains crystallized well in, and a plethora of other methods. We do get crystals, but they all diffract as salt. Most of these salts are found in wells containing a cation (ie. lithium sulfate, nickel chloride, magnesium acetate, cobalt chloride, etc.). When crystals are too small to shoot, I do set up optimized trays; however, if I get larger crystals, they diffract as salt as well. Most of these set ups, at this point, have also been conducted in hands other than mine and at other facilities known for their successful crystallization of proteins.
Has anyone else run into this problem and seen light at the other side?? Any suggestions are appreciated.
