I think we still have better luck with longer, slower, more gentle soaks - but its crystal-dependent. Try raising the [PEG] at the same time as you raise the [glycerol]. Phoebe
---- Original message ---- >Date: Fri, 31 Oct 2008 18:57:53 -0400 >From: Artem Evdokimov <[EMAIL PROTECTED]> >Subject: Re: [ccp4bb] Cryoprotectant for protein-DNA complex crystal >To: [email protected] > >Why soak for a whole minute? A single pass through cryo is usually enough, >and that takes a couple of seconds with the right set-up... > >You could try oil - if you're lucky it solves your issues. Note that not all >oils are the same, and many people succeed with blended compositions rather >than pure stuff. > >Finally, you could always try my humble recipe: > >http://www.xtals.org/crystal_cryo.pdf > >Good luck, > >Artem > >-----Original Message----- >From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of E >rajakumar >Sent: Friday, October 31, 2008 5:22 PM >To: [email protected] >Subject: [ccp4bb] Cryoprotectant for protein-DNA complex crystal > >Dear All >I am working on protein-DNA complex crystals for data >collection. These crystals are grown in 15-20 % of >PEG3350 or PEG4000 with pH of 6 to 7. When I soak the >crystals more than a minute in the cryo solution >(15-20% of Glycerol or ethylenglycol + reservoir) the >resolution of diffraction is becoming weak (reducing >to 6.0 A from 4.5 A) and also the spots are getting >spread (increase in mosaicity). Appears that Glycerol >or Ethylene glycol not good cryoprotectants in this >case. Is there any study on effect of cryoprotectant >on protein-DNA complex crystal and protein-DNA complex >dissociation? I also want to know which type >(organics, oils, polyols, sugars, polymers.) of >cryoprotectant is most preferred in protein-DNA >complex crystal. >Thanking you in advance >Rajakumara > > >E. Rajakumara >Postdoctoral Fellow > Strcutural Biology Program > Memorial Sloan-Kettering Cancer Center > New York-10021 > NY > 001 212 639 7986 (Lab) > 001 917 674 6266 (Mobile) > > > > Get your new Email address! >Grab the Email name you've always wanted before someone else does! >http://mail.promotions.yahoo.com/newdomains/aa/ Phoebe A. Rice Assoc. Prof., Dept. of Biochemistry & Molecular Biology The University of Chicago phone 773 834 1723 http://bmb.bsd.uchicago.edu/Faculty_and_Research/01_Faculty/01_Faculty_Alphabetically.php?faculty_id=123 RNA is really nifty DNA is over fifty We have put them both in one book Please do take a really good look http://www.rsc.org/shop/books/2008/9780854042722.asp
