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Crystallization screens and methods: Difference between revisions
→Desiccation of an existing screen which shows no sign of crystallization or precipitation
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* H. Schreuder et al. published a method to measure the dehydration effect of precipitants (J. Appl. Cryst. (1988). 21, 426-429.). This publication has tables of the chemical potential of water in solutions of MPD, NaCl, potassium tratrate and PEG 6K. | * H. Schreuder et al. published a method to measure the dehydration effect of precipitants (J. Appl. Cryst. (1988). 21, 426-429.). This publication has tables of the chemical potential of water in solutions of MPD, NaCl, potassium tratrate and PEG 6K. | ||
* similar experiments were done with NaCl, AS and MgSO4 by Arakali et al (Acta D 51 772-779, 2005) | * similar experiments were done with NaCl, AS and MgSO4 by Arakali et al (Acta D 51 772-779, 2005) | ||
* AmSO4, NaCl and PEGs were explored in J. Newman, [doi | * AmSO4, NaCl and PEGs were explored in J. Newman, [http://dx.doi.org/10.1107/S0907444905002726] Expanding screening space through the use of alternative reservoirs in vapor-diffusion experiments. Acta Cryst. (2005). D61, 490-493 | ||
* AmSO4 didn't work well; the ammonia changes the pH: Dunlop & Hazes, Acta Cryst D61, 1041-8, (2005) | * AmSO4 didn't work well; the ammonia changes the pH: Dunlop & Hazes, Acta Cryst D61, 1041-8, (2005) | ||
* Thakur AS, Robin G, Guncar G, Saunders NF, Newman J, Martin JL, Kobe B. [http://www.ncbi.nlm.nih.gov/pubmed/17971854?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum] Improved success of sparse matrix protein crystallization screening with heterogeneous nucleating agents. PLoS ONE. 2007 Oct 31;2(10):e1091. They used dried seaweed; horse hair; cellulose and hydroxyapatite. | * Thakur AS, Robin G, Guncar G, Saunders NF, Newman J, Martin JL, Kobe B. [http://www.ncbi.nlm.nih.gov/pubmed/17971854?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum] Improved success of sparse matrix protein crystallization screening with heterogeneous nucleating agents. PLoS ONE. 2007 Oct 31;2(10):e1091. They used dried seaweed; horse hair; cellulose and hydroxyapatite. | ||
further findings/ideas: | further findings/ideas: | ||
* LiCl seems to work very well in the reservoir, whereas in the droplet Li salts tend to increase the solubility of peptides (Seebach et al., | * LiCl seems to work very well in the reservoir, whereas in the droplet Li salts tend to increase the solubility of peptides (Seebach et al., Helv. Chim. Acta 72 (1989) 857-867) - but on the other hand Li salts can also be used as cryoprotectants. | ||
Helv. Chim. Acta 72 (1989) 857-867) - but on the other hand Li salts can also be used as cryoprotectants. | |||
* ~0.5 M LiCl match ~40% PEG4000 in chemical potential, and ~1.5-2 M LiCl match ~60-70% ammonium sulfate (~2.4 - 3 M). | * ~0.5 M LiCl match ~40% PEG4000 in chemical potential, and ~1.5-2 M LiCl match ~60-70% ammonium sulfate (~2.4 - 3 M). | ||
* at least 50% of PEG 4K, 8K, 10K desiccate drops. At less concentration PEGs seem to be poor. | * at least 50% of PEG 4K, 8K, 10K desiccate drops. At less concentration PEGs seem to be poor. | ||
* add 100% glycerol or ethylene glycol | * add 100% glycerol or ethylene glycol | ||
* a number of substances [like dryrite, calcium sulfate (the salt that is used to absorb the humidity in damp rooms), and the gel-like stuff that keeps diapers dry] were mentioned, but they seem less appropriate to the author, for different reasons. | * a number of substances [like dryrite, calcium sulfate (the salt that is used to absorb the humidity in damp rooms), and the gel-like stuff that keeps diapers dry] were mentioned, but they seem less appropriate to the author, for different reasons. | ||