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High concentration of ammonium formate is a cryosolvent On Mon, May 4, 2015 at 5:20 PM, Tristan Croll <[log in to unmask]> wrote: > What about nature's favourite cryoprotectant, trehalose? > > ________________________________________ > From: CCP4 bulletin board <[log in to unmask]> on behalf of Roger > Rowlett <[log in to unmask]> > Sent: Tuesday, 5 May 2015 7:22 AM > To: [log in to unmask] > Subject: Re: [ccp4bb] cryo condition > > We rarely use glycerol anymore, because it seems to fail so often for > many of our current proteins. Try glucose, 25-30%. This is most > conveniently done by weighing 125-150 mg of glucose in a microcentrifuge > tube, then addding well solution to the 0.5 mL mark and mixing until > completely dissolved. Then you can try dunking crystals in the cryo > solution, or, you can try the "no-fail" method (which does fail on > occasion) of cryoprotecting directly in the crystallization drop by slow > addition of the cryoprotectant. See > > http://capsicum.colgate.edu/chwiki/tiki-index.php?page=Mounting+Protein+Crystals > . > We have often found the slow addition of a glucose cryoprotectant works > for fragile, high solvent content crystals that are prone to cracking > under osmotic stress. > > Other alternatives include high concentrations of sodium malonate > (1-2M), or high concentrations of sodium formate (I think around 4 M?). > These could also be introduced gradually if required. > > Good luck! > > _______________________________________ > Roger S. Rowlett > Gordon & Dorothy Kline 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: [log in to unmask] > > On 5/4/2015 2:43 PM, Faisal Tarique wrote: > > Hello everyone > > > > Can anybody suggest me a cryo condition for a crystal obtained in > > MIDAS screen of Molecular Dimension: > > > > G1> 0.1MTris8.0G10.1Mpotassium chloride25% v/vSOKALAN®CP7 0.1MHEPES7.0 > > > > G2>0.3Mammonium formate20% v/vSOKALAN® CP 5 0.1MHEPES7.0 > > > > Crystals are in beautiful cuboid shaped but all sorts of PEG > > combinations and Glycerol formulation failed to prevent it from > > cracking and dissolving. > > > > Has anybody faced a similar situation as mentioned above and what > > precaution was taken to prevent it from cracking or dissolving. > > > > Your suggestions will be of immense help > > > > Thanks in advance >