I am working with a metalloprotein that binds cobalt and iron. I
was surprised that the solved structures showed the crystals
cryoprotected with glycerol are metal free while crystals
cryoprotected with ethylene glycol had the metals present. Both
cryoprotectant solutions contained metal in the 10 mM range and are
buffered at pH 9. I assume glycerol must be a weak chelator otherwise
it wouldn't be so ubiquitous in protein biochemistry. Has anyone else
experienced this before with glycerol?
Ho
UC Berkeley
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