[ccp4bb]: Summary PEG 550 MME

["Mark J. van Raaij" <m.vanraaij@chem.leidenuniv.nl>]

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The consensus seems to be that 30-35% PEG 550 MME can be used as 
cryo-protectant, with some successful cases at 20-25%. Of course, the 
proper thing to do is to check for glassy freezing with the other 
specific buffer components included, but this is a lot less fun than 
bothering the whole protein crystallography community.
Thanks to all helpful responses.

Original question:
Just a short practical question, not directly related to 
crystallographic computing (sorry): Has someone used PEG 550 MME 
successfully as cryo-protectant? If so, at what concentrations?

-- 
Mark van Raaij, m.vanraaij@chem.leidenuniv.nl