---------- Forwarded message ---------- From: Prem Prakash <prem...@gmail.com> Date: Fri, Dec 29, 2017 at 10:22 AM Subject: Re: [ccp4bb] how to improve the diffraction quality of the crystals and avoid icerings To: zaigham mahmood khan <mahmood.zaig...@gmail.com>
Hi, Yuvraj Initially I also faced similar problems, then I tried various combinations of different additives in the crystallization drop. Then I got relatively good diffraction data (2.8 Angstrm) in 0.01mM Bacl2 (in my case). In my protein structure I can see the Ba2+ ion bound to the intersubunit junctions which probably results some extent of decreased degree of freedom. Of course you also need the optimization of cryoprotectant as well as I can see Glycerol is giving you good resolution compare to others. Good luck Prem On Fri, Dec 29, 2017 at 2:06 AM, zaigham mahmood khan < mahmood.zaig...@gmail.com> wrote: > Yuvraj > > This is a tough call. may be you need to look at this database: > > http://web.archive.org/web/20111011202903/http://idb.exst. > jaxa.jp/db_data/protein/search-e.php > > Importantly, when you click on "ex" for the tab, "cryoprotectant", a > window will pop up and you can read different kinds of cryoprotectants that > have been successfully attempted in the past. Off-course, this also depends > on type of precipitant that you used for crystallization. Apparently, this > seems as glycerol worked better in your case, may be because you have > salt-based precipitant. > > > > Best wishes > > -Z > > > Zaigham Mahmood Khan, PhD > > Icahn School of Medicine at Mount Sinai > Department of Oncological Sciences > 1470 Madison Avenue > <https://maps.google.com/?q=1470+Madison+AvenueNew+York&entry=gmail&source=g> > New York > <https://maps.google.com/?q=1470+Madison+AvenueNew+York&entry=gmail&source=g> > > On Thu, Dec 28, 2017 at 8:28 AM, YUVARAJ I <yuvee...@gmail.com> wrote: > >> Respected All, >> I have crystallized a protein. It is forming big crystals, I have >> checked in the home source, >> Without cryoprotectant - No diffraction (blank) >> with Ethylene glycol- No diffraction (blank) >> with PEG 3350 - 7A diffraction and No ice rings >> with Glycerol - 3.5A diffraction with ice rings >> >> I have tried soaking with glycerol different concentrations 10-30% >> glycerol from 30 secs to 5 min. >> No improvement in the diffraction quality. >> >> How to improve the diffraction quality of the crystals and avoid the big >> ice ring. >> >> I have attached the diffraction image with this mail. >> >> Thanks in advance for your valuable suggestions >> >> Regards >> Yuvaraj >> >> >> -- >> >> >> >> >> >> >> >> >
