Working with isopropanol at room temperature and in a well ventialted environment is a nightmare. Everything moves around wildly until all the isopropanol has evaporated. Simply leaving the plate in the cold room for a couple of hours or overnight, and then doing all the mounting in the cold room and if possible with little air circulation will make life easier. There is less isopropanol evaporating from your drop, so there is less of the mixing effect that makes it nearly impossible to fish the crystals. Also, there is less evaporation in the loop in the 1 second or so it takes to freeze the crystal by plunging it in liquid Nitrogen, so the final concentration of isopropanol in the loop will be higher, which increases the chances of not needing any extra cryoprotectant.
Jose Antonio Cuesta Seijo. herman.schreu...@sanofi-aventis.com wrote: > Dear Chris, > > I recall from many years ago that we had a screening hit in high > isopropanol, which started boiling violently when we opened the well. We > "solved" the problem by using another precipitant but I would also be > interested in tricks how to handle high isopropanol. > > Best regards, > Herman > > > ________________________________ > > From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On > Behalf Of Chris Meier > Sent: Friday, April 09, 2010 10:39 AM > To: CCP4BB@JISCMAIL.AC.UK > Subject: [ccp4bb] freezing crystals grown in isopropanol > condition > > > > Dear all, > > I have a protein which crystallizes in 25% isopropanol, at > pH4.5. > > Does anyone have experience freezing crystals grown in such a > condition? > What cryoprotectants should I try? > Can isopropanol itself act as a cryoprotectant? > Any suggestions on how to deal with isopropanol evaporation > during mounting? > > Many thanks and best wishes, > Chris > > > > > -- *************************** Jose Antonio Cuesta-Seijo Biophysical Chemistry Group Department of Chemistry University of Copenhagen Tlf: +45-35320261 Universitetsparken 5 DK-2100 Copenhagen, Denmark ***************************
