A modification of this was done in pcr tubes, and it seemed to work even better:
Acta Cryst. (2004). D60, 203-204 [ doi:10.1107/S0907444903024491 ] An improved protocol for rapid freezing of protein samples for long-term storage J. Deng, D. R. Davies, G. Wisedchaisri, M. Wu, W. G. J. Hol and C. Mehlin Abstract: Freezing of purified protein drops directly in liquid nitrogen is a convenient technique for the long-term storage of protein samples. Although this enhances reproducibility in follow-up crystallization experiments, some protein samples are not amenable to this technique. It has been discovered that plunging PCR tubes containing protein samples into liquid nitrogen results in more rapid freezing of the samples and can safely preserve some proteins that are damaged by drop-freezing. The PCR-tube method can also be adapted to a PCR-plate freezing method with applications for high-throughput and structural genomics projects. On Mon, Nov 8, 2010 at 8:21 AM, Andrew Gulick <[email protected]> wrote: > We routinely use a P200 to pipette drops of protein directly into a small > Dewar of liquid nitrogen. The protein forms small BB’s with a volume of > approximately 30 micro-L each. Pipette slowly, allowing the drops to freeze > solid before adding the next one. The frozen BB’s can be picked up with > forceps or a slotted spoon and stored in a cryovial in the –80 freezer. For > future experiments, you can thaw only what you need. I have only seen one > protein that couldn’t recover from this and could only be crystallized prior > to freezing. > > A systematic study of this procedure is described in Deng et al. > http://www.ncbi.nlm.nih.gov/pubmed/14684931 > > --Andrew > > > > > On 11/5/10 3:40 PM, "<Eric Karg>" <[email protected]> wrote: > > Dear all, > > I'm working on a protein which starts to precipitate after 3-4 days of > storage at 4 degrees or room temperature. The storage buffer contains 300 mM > NaCl because at lower salt concentrations it also tends to precipitate. > Different buffers and adding glycerol did not help although this was not > done in a systematic way. Has anyone had similar experiences? Any > suggestions to overcome this problem? > > Thanks in advance! > > Eric > > > > -- > Andrew M. Gulick, Ph.D. > ----------------------------------- > (716) 898-8619 > Hauptman-Woodward Institute > 700 Ellicott St > Buffalo, NY 14203 > ----------------------------------- > Hauptman-Woodward Institute > Dept. of Structural Biology, SUNY at Buffalo > > http://www.hwi.buffalo.edu/Faculty/Gulick/Gulick.html > http://labs.hwi.buffalo.edu/gulick >
