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:[email protected]] On Behalf Of Stefan 
Münnich
Sent: 06 April 2011 09:33
To: [email protected]
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

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