Hi Donghui, I just want to draw your attention to the following article. It sums up suggestions which were already made by others for using concentrated (lithium) salt solutions for cryoprotection:
Rubinson, K.; Ladner, J.; Tordova, M. & Gilliland, G. Cryosalts: suppression of ice formation in macromolecular crystallography. Acta Crystallogr D Biol Crystallogr, 2000, 56 ( Pt 8), 996-1001 Good luck, christian wu donghui wrote: > Dear all, > > Recently, I got a crystallization condition as 0.1 M Bis tris ph 6.5, > 1.3M lithium sulfate, 0.1M NaCl, the shape of crystals is needle > cluster, very difficult to grow bigger, microseeding does not work, then > I tried macroseeding, and found crystal can grow bigger and rod like. > However as for the cryoprotectant, crystal will dissolve in > glycerol, ethylene glycol, MPD and PEG, even in the very low > concentration about 5%. I found my crystal can grow under the additive > 2-propanol in addition to the above mentioned crystallization condition. > I also noticed that Hampton cryoprotectant kit has the 2-propanol as > cryoprotectant. I want to know if anyone have ever used 2-propanol as > the cryoprotectant and what effect it might be. By the way Hampton > also mention lithium sulfate can be used as cryoprotectant, the > recommended maxium concentration is 2M, I tried and found ice ring is > severe and it is very easily to form lithium sulfate salt crystal at > this high concentration, I also tried sodium malonate, the > diffraction gave me few spots, resolution is only about 6--7 angstrom. > > Does anyone encounter such problem by lithium sulfate? > > > Welcome to any replies. Thanks a lot in advance. > > Donghui _______________________________________________________________________ Dr. Christian Biertümpfel Laboratory of Molecular Biology NIDDK/National Institutes of Health phone: +1 301 402 4647 9000 Rockville Pike, Bldg. 5, Rm. B1-03 fax: +1 301 496 0201 Bethesda, MD 20892-0580 USA _______________________________________________________________________
