Hi, Yuvraj, I can suggest two methods: 1) collect a dataset at room temperature 2) crystallize your protein in cryoconditions. That is add 25 % of glycerol to your crystallization conditions and perform small optimization in terms of precipitant concentration.
2017-12-29 7:55 GMT+03:00 Prem Prakash <prem...@gmail.com>: > > ---------- 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.ja >> xa.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 >>> >>> >>> -- >>> >>> >>> >>> >>> >>> >>> >>> >> > > -- Eugene Osipov Junior Research Scientist Laboratory of Enzyme Engineering A.N. Bach Institute of Biochemistry Russian Academy of Sciences Leninsky pr. 33, 119071 Moscow, Russia e-mail: e.m.osi...@gmail.com
