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# Set your screens at different temperature. 25 and 4 degrees are the most popular options. If you completely lost hope for your original screens, just transfer them to the cold room. Protein solubility will change and you may get crystals. | # Set your screens at different temperature. 25 and 4 degrees are the most popular options. If you completely lost hope for your original screens, just transfer them to the cold room. Protein solubility will change and you may get crystals. | ||
# Add a purification step. Purity can be critical to protein crystallization and the purity judged from SDS-PAGE or even gel filtration can be misleading. | # Add a purification step. Purity can be critical to protein crystallization and the purity judged from SDS-PAGE or even gel filtration can be misleading. | ||
# There are other screens. While it is proably true that when proteins do crystalize, they in many cases produce hits from Hampton screens I or II, we are dealing here with exception to that rule. Lists of screens are available from manufacturer websites: | # There are other screens. While it is proably true that when proteins do crystalize, they in many cases produce hits from Hampton screens I or II, we are dealing here with exception to that rule. Lists of screens are available from manufacturer websites: | ||
#* [http://www.hamptonresearch.com/ Hampton Research] | #* [http://www.hamptonresearch.com/ Hampton Research] | ||
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#* [http://www.emeraldbiosystems.com Emerald Biosystems] | #* [http://www.emeraldbiosystems.com Emerald Biosystems] | ||
#* [http://www.jenabioscience.com/cms/en/1/browse/632_screens.html Jena Bioscience] | #* [http://www.jenabioscience.com/cms/en/1/browse/632_screens.html Jena Bioscience] | ||
#* [[Crystallization screens and methods | | #* [http://www.moleculardimensions.com Molecular Dimensions] | ||
#* See also [[Crystallization screens and methods]] | |||
# [[Modifying_the_protein_to_crystallize_better | Modify your protein. ]] | |||
==Improving crystals== | ==Improving crystals== | ||
===Reducing the mosaicity=== | ===Reducing the mosaicity=== | ||
Things to try | |||
Things to try concerning crystallization - see also [[Improving crystal quality]]. | |||
For cryo question see [[cryo]] and [[Data collection: Tips and Tricks]]. | |||
* change precipitant, pH, temperature; try additives | |||
* try co-crystallization with glycerol (2%, 5% or 10%). | |||
* incubate your crystal longer in your cryo/stabilization solution. | |||
* optimize the cryo conditions | |||
* anneal (freeze/thaw) the crystal - '''DISCLAIMER''': your mosaicity can go up as well as down with annealing | |||
* the mosaicity may be anisotropic, so try to orient the crystal in the loop such that you can shoot along a different axis | |||
* look at Elspeth Garman's papers, and/or check her talks at RapiData workshops (anybody with a link??) | |||
==References== | |||
* J.W. Pflugrath (2004) Macromolecular cryocrystallography—methods for cooling and mounting protein crystals at cryogenic temperatures. ''Methods'' '''34''', 415-423 http://dx.doi.org/10.1016/j.ymeth.2004.03.032 | |||
* papers listed at http://www.px.nsls.bnl.gov/courses/papers/ZD_EG_papers.html | |||
* H.D. Bellamy, E.H. Snell, J. Lovelace, M. Pokross and G.E.O. Borgstahl (2000) The high-mosaicity illusion: revealing the true physical characteristics of macromolecular crystals. ''Acta Cryst.'' '''D56''', 986–995 |
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