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Mitegen makes a nice little product that is a plastic tube that will slide over one of their magnetic cap/loops. If you put some well solution in the tube and seal the base with apiezon, you can collect quite a bit of data on the loop mounted crystal before it dries out. Cheers, _______________________________________ 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 Thu, Aug 2, 2012 at 2:14 PM, Yi-Liang Liu <[log in to unmask]> wrote: > Hi Herman and other CCP3BBers, > > Thanks for your suggestions. I didn't see any cracks in the crystal drops > initially. I will certainly try to shot crystals under room temperature and > see what happens. Does the plastic loops fit into the cryo stands Molecular > Dimension sells? > > LUcas > On Aug 2, 2012, at 2:24 AM, [log in to unmask] wrote: > > > Hi Lucas, > > > > The funky diffraction pattern is most likely due to a cracked crystal, > > resulting in a mixture of slightly differently aligned diffraction > > patterns. Were the cracks there before you added the cryprotectant? If > > not, the cryoprotectant is definitively to blame. As has mentioned > > before, you have to take a shot at room temperature without any > > cryoprotectant added, to make sure the bad quality is not due to the > > cryoprotectant. Mitegen sells plastic capillaries, which you can slide > > over your loop to prevent the crystal from drying out. > > > > Good luck! > > Herman > > > > -----Original Message----- > > From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of > > Yi-Liang Liu > > Sent: Thursday, August 02, 2012 4:15 AM > > To: [log in to unmask] > > Subject: Re: [ccp4bb] Enhancing Crystal Quality > > > > Hi, > > > > Thanks for the kindly answers from everyone. I actually haven't tried > > different cryoprotectants. I might will give a try next time. I usually > > only use mother liquor+30% PEG400. It is noticeable that it has some > > "patterns (cracks (?))" on the crystal. However, it didn't form icy > > rings or etc. The diffraction pattern looks funky too. It looks like it > > is twin and the diffraction spot has tails. Does this indicate the > > cryoprotectant problem? > > > > Lucas > > On Aug 1, 2012, at 2:11 PM, Antony Oliver wrote: > > > >> Have you tried different cryoprotectants? Can make a huge difference. > > Also, have you shot an xtal at room temp - to see what the intrinsic > > diffraction limit is? Additive screens? If all else fails you may well > > need to explore a different expression construct. > >> > >> Tony. > >> > >> Sent from my iPhone > >> > >> On 1 Aug 2012, at 19:52, "Yi-Liang Liu" <[log in to unmask]> wrote: > >> > >>> Hi CCP4BBers, > >>> > >>> I have a protein crystallized with 0.2mM Mg acetate and PEG 8000 or > > 0.1mM cacodylate, pH 6.5, 0.2 Mg acetate, PEG 3350. Both of the > > conditions gave triangle pyramid like crystals. I brought the crystals > > to synchrotron using 30% PEG 400 as cryoprotactant, the resolution was > > only be able to reach 4A or worse. I have tried changing pH and > > concentrations of PEG, PEG types. I found out this crystal only grew > > between pH 6.5~7.5 and PEG types did not change the result of > > diffraction dramatically. I have also tried the seeding (break it down > > and reseed in the same condition. Maybe I did it wrong?). It gave me the > > similar results, not improving. Is there any simple way of improving it > > before jumping into reengineering the protein. > >>> > >>> Thanks, > >>> > >>> Lucas >