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Re: [ccp4bb] crystallisation |
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CCP4bb navigationCCP4bb <-- 2008 <-- June 2008 <-- 03 June 2008Subject: Re: crystallisation From: Kevin Jude kjude {- at -} BERKELEY {- dot -} EDU Date: 2008-06-03 glycerol has proved a good cryoprotectant in my hands. kmj Phoebe Rice wrote: > If you have high [DTT] in your buffer, you might be > catalyzing the addition of dimethyl arsenic (from the > cacodylate) to some of your cysteines? > Also, 10% glyercol sounds quite low for reproducibly good > freezing (at least in my experience). > Phoebe > > ---- Original message ---- >> Date: Mon, 2 Jun 2008 17:04:38 +0100 >> From: sajid akthar >> Subject: [ccp4bb] crystallisation >> To: CCP4BB@JISCMAIL.AC.UK >> >> >> Dear All >> >> My protein size is ~30kD and crystallizes with >> 19%Peg3350, 0.2M Nacl, and 0.1M Na Cacodylate buffer. >> >> Please refer the attached crystal image with this. The >> crystal looks like good enough for home source. These >> crystals appears in 4-5 days at room temp. >> >> Sometimes I'm getting crystals like this, but very few >> in 24 well tray. Most of the time, I found the drop >> contains needles. If I reduce the precipitant little >> bit, I wont find any change in the drop even after >> long time. Changing pH (or temp)of the buffer does not >> help me any better. The crystal appears only around >> 5.5pH. >> >> The problem is mosaicity. This crystal diffracted in >> home source upto 3.2A and the mosaicity is 2.5degree. >> Almost all the good crystal like this having same >> mosaicity. >> >> Good cryo condition so far that I found was >> 10%Glycerol with mother liquor. Other conditions >> weekens the diffraction quality or increase mosaicity. >> >> In many crystal I could see some crack in the middle >> of the crystal, it looks like twin crystal. Or the >> crystal appears with some sattelite crystals. >> >> Can anyone suggest me some good way to overcome these >> problems. >> >> Thankz >> >> Sajid >> >> >> >> From Chandigarh to Chennai - find friends all over > India. Go to http://in.promos.yahoo.com/groups/citygroups/ >> ________________ >> DSCN0003.JPG (720k bytes) > 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 CCP4bb navigationCCP4bb <-- 2008 <-- June 2008 <-- 03 June 2008 |
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