I should point out that the reference I gave is quite misleading as the samples studied contained lecithin Apologies Colin
> -----Original Message----- > From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of > Colin Nave > Sent: 06 April 2011 18:33 > To: CCP4BB@JISCMAIL.AC.UK > Subject: Re: [ccp4bb] **Possible spam**Re: [ccp4bb] FW: [ccp4bb] > diffraction of spherulites > > First few reflections seem characteristic of lamellar (rather than 3D > crystals). Might be something other than PEG but see > > Magda El Nokaly, Stig E. Friberg, David W. Larsen, Lyotropic liquid > crystals from lecithin, water, and polyethylene glycol, Journal of > Colloid and Interface Science, Volume 98, Issue 1, March 1984, Pages > 274-276, ISSN 0021-9797, DOI: 10.1016/0021-9797(84)90507-1. > (http://www.sciencedirect.com/science/article/B6WHR-4RKW3SB- > 19/2/795b52beefd22e48f1958c167d9f4d0a) > > > Colin > > > -----Original Message----- > > From: Jacob Keller [mailto:j-kell...@fsm.northwestern.edu] > > Sent: 06 April 2011 18:16 > > To: Nave, Colin (DLSLtd,RAL,DIA) > > Cc: CCP4BB@jiscmail.ac.uk > > Subject: **Possible spam**Re: [ccp4bb] FW: [ccp4bb] diffraction of > > spherulites > > > > It seems hard to imagine what there is anything in his solutions > other > > than protein that would make spherulites, no? PEG 8000 at 12% seems > > pretty benign, unless the trays or screens have been sitting around > > for quite a while... > > > > JPK > > > > On Wed, Apr 6, 2011 at 12:04 PM, Colin Nave > <colin.n...@diamond.ac.uk> > > wrote: > > > > > > > > > Stefan > > > > > > Could the low angle reflections be from lamellar liquid crystals of > > the PEG > > > (or a mixed PEG/water phase). Seems like you have 1st,2nd and 4th > > order > > > reflections with presumably the 2nd order about 20A. > > > > > > I think 40A lamellar spacing is characteristic of some PEG liquid > > crystals. > > > > > > Colin > > > > > > > > > > > > > > > > > > From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf > Of > > Stefan > > > Münnich > > > Sent: 06 April 2011 09:33 > > > To: CCP4BB@JISCMAIL.AC.UK > > > Subject: [ccp4bb] diffraction of spherulites > > > > > > > > > > > > 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 > > > > > > > > -- > > ******************************************* > > Jacob Pearson Keller > > Northwestern University > > Medical Scientist Training Program > > cel: 773.608.9185 > > email: j-kell...@northwestern.edu > > *******************************************
