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Along with all the excellent suggestions so far you can also try no cryoprotectant at all: If you harvest your crystal on a mesh loop and remove all the mother liquor the crystal lattice itself will act as a cryoprotectant as long as the solvent channels are smaller than 40A in diameter (they usually are). Shameless self citation: http://scripts.iucr.org/cgi-bin/paper?S0907444911031210 Best wishes, Matt. On 05/05/2015 13:16, Clemens Grimm wrote: > Hi Faisal, > > Did you try to simply raise the Sokalan CP7 percentage? Additives like > Glycerol can increase the solubility of proteins, in that case you > have to counteract by increasing also the precipitant concentration. > > If your crystals crack, a likely reason is osmotic shock. Particularly > large crystals tend to be problematic. It is in general advisable to > transfer the cryo protectant onto the crystal within the mother > liquor rather than fishing the crystal out with a loop. In addition, > it might be necessary to prepare intermediate concentration of the > cryo protectant by mixing with reservoir solution and do a stepwise > increase. I had several projects with very large crystals that > definitely needed at least five gradual steps over a time span of more > than half an hour to extract datasets with reasonable mosaicity. > > Sokalan CP7 is an acrylate copolymer. Therefore, low molecular weight > sodium polycralyte as a cryo protectant (e. g. Aldrich #420344) might > be worth a try, possibly also in combination with some amount of good > old glycerol, PEG, Trehalose, TMAO etc. > > Best wishes, > Clemens > > > Zitat von Faisal Tarique <[log in to unmask]>: > >> 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 >> -- >> Regards >> >> Faisal >> School of Life Sciences >> JNU > > > > -------------------------------------------------- > Dr. Clemens Grimm > Institut für Biochemie > Biozentrum der Universität Würzburg > Am Hubland > D-97074 Würzburg > Germany > e-mail: [log in to unmask] > phone : +49 0931 31 84031 > ------------------------------------------------- > -- Matthew Bowler Synchrotron Crystallography Group European Molecular Biology Laboratory 71 avenue des Martyrs CS 90181 F-38042 Grenoble France =================================================== Tel: +33 (0) 4.76.20.76.37 Fax: +33 (0) 4.76.20.71.99 http://www.embl.fr/ ===================================================