Hi Yuvaraj, the importance of proper cryo mounting is under-appreciated in the community. Intensities of reflections on or close to ice rings cannot be recovered by the data processing software with good accuracy, which is detrimental for structure solution and refinement. Thus it is vital to avoid or at least minimize ice rings!
Whenever I see real experts flash-freezing crystals and mounting them, I am impressed by their speed, diligence, and care for the details. I get the impression that some labs educate students properly, whereas that knowledge is apparently not available in others. https://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php/Cryo has some useful hints and references. Unfortunately, I don't have a list of more recent publications which emphasize the details - others may fill this in. An overview video is https://www.youtube.com/watch?v=FENUWRYXMOM - good music but no explanations. https://www.youtube.com/watch?v=QcsaWowulDM has explanations, and so has https://www.youtube.com/watch?v=yyY01zW_oaI . good luck, Kay On Thu, 28 Dec 2017 18:58:57 +0530, YUVARAJ I <[email protected]> wrote: >Respected All, > I have crystallized a protein. It is forming big crystals, I have checked >in the home source, >Without cryoprotectant - No diffraction (blank) >with Ethylene glycol- No diffraction (blank) >with PEG 3350 - 7A diffraction and No ice rings > with Glycerol - 3.5A diffraction with ice rings > >I have tried soaking with glycerol different concentrations 10-30% glycerol >from 30 secs to 5 min. >No improvement in the diffraction quality. > >How to improve the diffraction quality of the crystals and avoid the big >ice ring. > >I have attached the diffraction image with this mail. > >Thanks in advance for your valuable suggestions > >Regards >Yuvaraj > > >-- >
