Have you thought about a quick dip in Paratone N or other oils then immediately plunging into liquid nitrogen? I would make a 65% Paratone N/35% Dioxane mix, then run the crystal thru it and snap freeze in liquid nitrogen.
Good luck! Bryan From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of [email protected] Sent: Thursday, October 21, 2010 3:48 PM To: [email protected] Subject: Re: [ccp4bb] **Possible spam**cryoprotetant for 35% Dioxane 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 -------------------------------------------------------------------------- Confidentiality Notice: This message is private and may contain confidential and proprietary information. If you have received this message in error, please notify us and remove it from your system and note that you must not copy, distribute or take any action in reliance on it. Any unauthorized use or disclosure of the contents of this message is not permitted and may be unlawful. -----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 =
