Dear CCP4
I looped a v.thin rod emerging from a cluster of v.thin rods that grew in 29%PEG1500 and 0.1M SPG buffer at pH7.5 (succinic acid, sodium dihydrogen orthophospate and glycine). The loop i used had been washed more than 10 times with deionised water (so assumed as 'clean'). The crystals had grown at 17degreesC, and looped out probably just below room temperature (~20-23 degreesC). When transferred to 5% glycerol cryo-buffer the crystal disintegrated (maybe due to glycerol being an unfavourable addition to the mother-liquor). When i looked back at the original cluster-containing drop, a very tough shell had formed over the surface of the drop, from which chunks could be dug out...the nearest analogy is maybe like when you blow-torch sugar on top of creme brulee, and have to crack it with your spoon. The crystals within had also disintegrated. Any clues to what might have caused this very tough shell to form, and maybe how to deal with it?
Much appreciated
Rick Salmon
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