I collected on 20% and 25% PEG4000 the trick though was small crystals (<100µm longest dimension) so the liquid can freeze (is that the right word, considering the 80+ thread we recently had) fast by plunging the mounted crystal into liquid nitrogen. A faint ice ring was still visible but didn't harm. The previous suggestion with supplementing PEG400 into the mix is what I typically do. Keep your 30% PEG4000 and add either glycerol or PEG400, the latter is more safe as it is more similar.
Good luck, Jürgen On Nov 30, 2012, at 9:12 PM, Jackie Vitali wrote: I would try your motherl liquor augmented with 10 per cent PEG 400 hoping for the best. Better yet mount your crystal inside a capillary like old times & measure room temp data. At least you have something for sure. Finally I have heard (never did it) that if you do not have air on top of your dewar (like nitrogen atmosphere) you do not need cryoprotectant. In my hands PEG4000 is not a cryoprotectant but adding 5 to 10 per cent PEG400 does the job. If I had an option I would go for room temp data in a home source. Sent from my iPhone On Nov 30, 2012, at 8:22 PM, Yuri Pompeu <yuri.pom...@ufl.edu<mailto:yuri.pom...@ufl.edu>> wrote: Dear community, I have what seems to be a pretty decent single crystal that grew from a screen set up 2 weeks ago. I am trying to reproduce it but so far I have not succeeded. I am however afraid the crystal that did form will start to deteriorate. So this brings me to dilemma, I feel like I should try and mount this crystal and shoot it. But since I only have 1 sample, I do not want to mess this up... I am inclined to try cryo conditions, but I am afraid the addition of a cryo such as glycerol could destroy the little guy. The crystal formed in 30% PEG 4000, 0.1M NaCitrate pH5.6 and 0.2M NH4AcO, I wonder if this is a cryo condition already? Any suggestions would be appreciated. best, ...................... Jürgen Bosch Johns Hopkins University Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Office: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-2926 http://lupo.jhsph.edu
