Hi, In our hands, the crystallisation droplets of glycosomal pyruvate phosphate dikinase had a 'skin' of what I thought was denatured protein at the surface of every crystallisation droplet. We had to learn to use the crystal microtools (such as a microknife, or a micro-needle can't remember what we have - sold by Hampton Research and I do not own shares in this company) to be able to cut this skin and drag it to the side of the droplet before being able to suck out the crystals. A bit like dissection under the binoculars.
Fred. > Message du 25/11/10 15:56 > De : "Rick" > A : CCP4BB@JISCMAIL.AC.UK > Copie à : > Objet : [ccp4bb] Tough 'shell' on disturbed drop > > 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
