Hi All, I have an RNA-binding protein that I can purify out of bacteria in PBS (Phosphate buffered saline;137 mM NaCl, 2.7 mM KCl, 10 mM Na2HPO4, 2 mM KH2PO4), but which is insoluble in Tris/NaCl-based buffers. My guess would be that the inorganic phosphates (by mimicking RNA) are binding the protein to keep it in solution. My question is whether I can leave the protein in a phosphate-based buffer (at lower salt maybe) to set up crystallization trials or are PBS-based buffers not suitable for crystallization in general. I have always used Tris/NaCl based buffers in the past.
Thanks in advance for your suggestions. Regards, JK
