Dear Lokesh, Actually I have tried to dip my crytal directly into mineral oil, no ice ring, but also no diffraction, which might indicate crystal packing under mineral oil is not stable. Anyway, thanks a lot for your valuable information. Other friends mention the use of LiCl or Lithium formate as cryoprotectant, I will try these immediately and will let you know if it works.
Best regards, Donghui On 2/27/08, Lokesh Gakhar <[EMAIL PROTECTED]> wrote: > > Hi Donghui, > > Have you tried mineral oil? That has sometimes worked for us when other > cryoprotectants have given problems. > > -Lokesh > > On Tue, Feb 26, 2008 at 9:30 PM, wu donghui <[EMAIL PROTECTED]> 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 > > > >
