Hi Catherine, If they are indeed salt crystals, have you tried preparing different truncations of the gene encoding your target? I've seen a number of successes in which, after a codon or two was added to the termini of the gene being overexpressed, the target crystallized beautifully.
Best, Chris On Wed, Jul 16, 2014 at 9:55 AM, Bishop, Catherine E. <cati...@ou.edu> wrote: > 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. > >
