Having grown crystals with dioxane as precipitant, I can tell you that harvesting them isn't easy - as is the case for most crystals grown in volatile precipitants. At the time, we used an increased amount of dioxane plus 2-propanol as additive to further stabilize the crystal. (Yes, that makes the harvesting yet harder). Nothing else I remember trying actually worked (specifically, I remember that glycerol did not work at all, any glycerol addition dissolved the crystals).
Cryoprotection is of course trial-and-error, like crystallization itself. Hopefully you have plenty of crystals to 'play' with. In case you had luck with the screening condition, but have not repeated crystal growth with a home-made equivalent, let me tell you another story. When I got my initial hit with dioxane, I was not able to repeat it with a home-made precipitant that was "the same" as the screen. We guessed that the difference was in the dioxane. I borrowed multiple bottles from other labs and found that only one out of six worked. We kept the bottle and bought the lab we borrowed from a new bottle. We never figured out what was present in the "magic" bottle, or alternative what was absent in it and present in all other bottles that made the difference. I went as far as talking to manufacturers about lot numbers and the differences (we bought the same brand and grade as the dioxane in the screen, but it was a different lot number) and all that I "learned" from that was that I wasn't supposed to keep any dioxane around (because it is an ether and it potentially forms peroxides). I already knew this, but wasn't interested - I just wanted more crystals! Hope your crystals and dioxane are more cooperative. Mark -----Original Message----- From: Jerry McCully <[email protected]> To: [email protected] Sent: Wed, Oct 20, 2010 6:00 pm Subject: [ccp4bb] **Possible spam**cryoprotetant for 35% Dioxane Dear All; We just got some crystals from 35% (v/v) Dioxane. We are going to collect some data soon. Does anyone have the experience with the cryoprotectant in this condition? Thanks a lot, Jerry McCully =
