You can also try to use the micromount loops (look like ink-pen nibs) sold by Mitegen. They are a much easier alternative to capillary mounts; they are easy to handle and work well for room temperature data collection.
Good luck. Raji ---------Included Message---------- >At the risk of sounding too commercial, here are some suggestions: > >1. See if you can either place your crystallization tray in a cold room or >crystallize it there. Mount your crystal in a capillary here so that at >whatever lower temperature you use, the distillation of solvent will be >reduced. > >2. If capillaries are too hard to work with, even a quick diffraction image >out of a loop, while the crystal is drying out, may give you some >information. Alternately, I have saturated my stock solution with sugar >from the coffee room and swished my crystal through this for getting a quick >diffraction image. In a rare case, the crystal actually diffracted for >several hours at room temperature. > >3. Someone mentioned using Paratone oil. This is good, but a little thick >and sticky. So, I use PerFluoroPolyEther (PFPE) as it is much less viscous >and is colorless. I buy FOMBLIN Y VAC 14/6 from SigmaAldrich (Cat # >317934-100G). PFPE is mildly hydroscopic, so it is best to open the bottle >infrequently (I withdraw ten 0.5 ml aliquots whenever I open the bottle). > >4. The Free Mounting System (FMS) is ideal for RT screening. So long as >you do not have a highly volatile component in solution, then you can use >the standard FMS at temperatures in the range of 15 to 25 C. If you do have >a volatile component, then Proteros bistructures GmbH (www.proteros.com) has >the only FMS with the capability of adding solvents to the gas stream...and >with some compensation, they will gladly help you with this. > >Kris > >------------ >Kris F. Tesh, Ph D >Director, Macromolecular Products >Rigaku Americas Corporation >9009 New Trails Drive >The Woodlands, TX 77381 USA >001 281 362 2300 x 144 >-----Original Message----- >From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of >Benini, Stefano >Sent: Wednesday, July 11, 2007 7:17 AM >To: CCP4BB@JISCMAIL.AC.UK >Subject: Re: [ccp4bb] Help with reducing crystal mosaicity > >Dear Mary, > >the problem encountered with cryoprotectans is the change in the solution >surrounding your crystal as they may not be present in your crystallisation >conditions or you need to increase their concentration to make them act as >cryoprotectant. >So I don't thik is the cryoprotectant itself as it is you mother liquor.. > >test it in a capillary so you could rule out that freezing is the problem > >of course you don't want to find new crystallisation conditions when you >tried everything and I know what it means!! > >I would try to improve crystal quality using additives or ligand etc...., > >your long axis is very worrying as well!!! may be some magic additive could >change the packing and givew better diffraction too > >I also had crystals growing from MPD, unfortunately there was a >non-cleavable his-tag >so I could not hope that metals would help..... and other additives did not >make any difference >then my contract finished and so did the project! > >I hope you still have a lot of time available to try different things but I >would not waste time trying to change your cryo > >ciao > >Stefano > >Stefano Benini PhD >AstraZeneca UK >Structural Biology >Mereside 50S38 >Alderley Park > > > > > > > > >-----Original Message----- >From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] Behalf Of >Patrick Shaw Stewart >Sent: 11 July 2007 12:10 >To: CCP4BB@JISCMAIL.AC.UK >Subject: Re: [ccp4bb] Help with reducing crystal mosaicity > > >Just a thought, Mary - going back to your original question about MPD. I >extracted the crystallization conditions from REMARK 280 of 3939 PDB entries >a couple of years ago. The average concentration of the MPD used was high - >38.6%, while PEGs tended to be used at lower concs, e.g. PEG400 25.7%. You >can see the data at www.douglas.co.uk/top14.htm > >I thought this information could be useful if you want to replace some of >the MPD with another precipitant (or cryoprotectant). > >Best wishes > >Patrick Shaw Stewart > > >-- >[EMAIL PROTECTED] Douglas Instruments Ltd. >DouglasHouse, EastGarston, Hungerford, Berkshire, RG177HD, UK >Directors: Peter Baldock, Patrick Shaw Stewart, James Smith >http://douglas.co.uk or http://www.douglasinstruments.com >Tel: 44 (0) 148-864-9090 US toll-free 1-877-225-2034 >Regd. England 2177994, VAT Reg. GB 480 7371 36 > > >> -----Original Message----- >> From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Mary >> Fitzgerald >> Sent: 09 July 2007 23:05 >> To: CCP4BB@JISCMAIL.AC.UK >> Subject: [ccp4bb] Help with reducing crystal mosaicity >> >> Help please! >> >> I'm looking for some new ideas. I have crystals that come out of a >> sitting drop with a mixture of sodium cacodylate at pH 6.5, magnesium >> acetate and MPD for the well solution. The MPD concentration is >> sufficient to act as a cryoprotectant. Currently, I directly freeze >> these crystals in liquid nitrogen. When I collect data, I typically >> have high anisotropic mosaicity; it ranges from 0.8 to 1.2. This is >> further complicated with a weakly diffracting crystal (4-5 A) that has >> a long unit cell axis of ~500 and often twinning. >> >> It has been suggested to me that the cryoprotectent is a problem. I >> haven't checked the diffraction at room temperature, yet. Please no >> suggestions of finding a different crystal form as that's not a >> consideration at the moment. I have my reasons. I did find one >> crystal that has lower mosaicity (0.5 to 0.8) but had weaker >> diffraction then the typical crystal. Attempts at flash cryoannealing >> have not helped. >> >> So, what's a good way to change the cryoprotectant if the >> cryoprotectant is the precipitant? I've considered trying dehydration >> but wasn't certain if that would help with the mosaicity. >> >> Thanks for any ideas, >> >> Mary X. Fitzgerald >> Postdoctoral Associate > ---------End of Included Message----------
