Dear All, I am working on a protein structure that yielded comparable diffraction quality crystals from two different crystallization condition. One of the crystallization condition conatins high conc. of salt pptant whereas the oher one contains high conc. of organic pptant. There are some minor differences in the stucture with respect to the backbone but what most surprising is the oligomeric structure. AnSEC study suggest the protein to be a tetramer in solution and a tetrameric assembly is observed in the asymmetric unit of the space group of the crystal obtained from high conc. of organic pptant. However, the crystal structure from the high conc. of salt pptant does not reveal any oligomeric assembly - symmetry operations of the space group does not suggest any oligomeric assembly. I believe the high salt conc. disrupted the tetrameric assembly and enabled crystallization of the protein as a monomer.
Curious to know if there has been any similar precedence before. Cheers, Shiva
