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Getting better xtals

Eric Toth toth
Fri Jul 28 16:54:02 EST 1995

Well, the idea in a case like this is to preferentially slow down growth in
the direction that is growing very rapidly and hope that the direction that
grows slowly will increase in size.  Most people try stuff like divalent
cations (although in your case since you are probably using citrate as a
buffer, compounded with the fact that you have ammonium sulfate as a
precipitant, you'll
run the risk of getting nice-looking salt crystals and get no improvement in
your protein crystal morphology).  Of course if there is some easy way to
distinguish your protein from salt (i.e. it is colored) this shouldn't be a
problem.  You should also try organics (dioxane and DMSO seem to be the most
popular, but try anything you can get your hands on).  The final thing that
might help is using detergents like beta-octylglucoside at low concentrations
(0.1-0.5% w/v).  If that doesn't work, you could maybe try DTT or
2-mercaptoethanol.  If nothing works, try pissing on them.  It probably won't
help, but it may make you feel better :-)  Good luck.

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