[ccp4bb] Crystallization of low solubility proteins from glycerol-containing solutions

[Roger Rowlett]

Does anyone have practical experience crystallizing low solubility proteins from solutions containing significant (10-20%) glycerol? We can get small crystals by mixing 4:1 ratios of protein to well solution, but the drops do not concentrate back to the well solution volume as anticipated, even if the well solution is brought to 10-20% glycerol as well to balance osmolarity. Concentration of the protein further to reduce the protein:well solution ratio may not be practical (it crashes out) even in 20% glycerol. Unfortunately, glycerol seems to be required to maintain protein solubility, so that may not be practical to remove either. One thought is to add additional osmolyte to the well solution to draw down the drop volume once small crystals form, a kind of a "macro-seeding" approach, but I am not aware of a systematic way of doing this. Anyway, I am almost certain I am trying to re-invent the wheel,as someone has probably done something similar. Any suggestions would be appreciated. Cheers, -- Roger S. Rowlett Professor Department of Chemistry Colgate University 13 Oak Drive Hamilton, NY 13346 tel: (315)-228-7245 ofc: (315)-228-7395 fax: (315)-228-7935 email: rrowl...@colgate.edu