Hi Dave, thanks for your reply. Is there any chance of telling whether it is salt or protein from the diffraction image?
Stefan On Apr 6, 2011, at 12:16 PM, David Briggs wrote: > Hi Stefan, > > It looks like a powder diffraction-type image. > > http://en.wikipedia.org/wiki/Powder_diffraction > > You can imagine that your spherulites are made up of many small > crystals in random orientations, a bit like a powder - this means that > rather than getting discrete diffraction spots as you would hope to > see for a single crystal, you see diffraction rings around the beam > centre. > > HTH, > > Dave > > ============================ > David C. Briggs PhD > Father, Structural Biologist and Sceptic > ============================ > University of Manchester E-mail: > david.c.bri...@manchester.ac.uk > ============================ > http://manchester.academia.edu/DavidBriggs (v.sensible) > http://xtaldave.wordpress.com/ (sensible) > http://xtaldave.posterous.com/ (less sensible) > Twitter: @xtaldave > Skype: DocDCB > ============================ > > > > On 6 April 2011 09:32, Stefan Münnich <smunn...@vub.ac.be> wrote: >> Hey guys, >> >> When I collect data from these spherulites/crystals (grown in 0.1 M sodium >> acetate, 0.1 M MOPS pH 7.5, 12 % (w/v) PEG-8000, protein buffer: 100 mM >> NaCl, 50 mM HEPES pH 7.5): >> http://img695.imageshack.us/i/cryst.png/ >> I get this diffraction pattern: (it's not cryo protected, so there's some >> ice-rings also) >> http://img683.imageshack.us/i/diffv.jpg/ >> >> It can't be only ice-rings because those are usually starting at something >> like 3.8 A, whereas I already got one ring directly around the beam center >> and also one at about 20 A. >> Has anybody seen anything like that and tell me what it is? >> >> Stefan
