Hi all I am dealing with a protein which size is about 200kDa. Due to the impurity and degradation problem, the protein has gone thru 3 purification steps (affinity column > ion exchange column > gel filtration column). The buffer condition for the last step of purification was 50mM MOPS pH7.0, 500mM NaCl, 20% glycerol, and 1mM DTT. Although there are few crystals were observed in different buffer condition, but they are too small and fragile and almost no diffraction at all. I have tried to optimize crystallization condition in 24-well format by hanging drop of equal volume of protein and buffer, but it is not producible. I believed that my protein might have conformational change and I have no idea how to solve it. Please advice Thanks vid
