Re: [ccp4bb] crystallisation

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CCP4bb <-- 2008 <-- June 2008 <-- 03 June 2008

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Subject: Re: mosaicity,was:crystallisation
From: Tommi Kajander tommi {- dot -} kajander {- at -} HELSINKI {- dot -} FI
Date: 2008-06-03

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Subject: Re: crystallisation
From: Kay Diederichs kay {- dot -} diederichs {- at -} UNI-KONSTANZ {- dot -} DE
Date: 2008-06-03

Subject: Re: crystallisation
From: Juergen Bosch jbosch {- at -} U {- dot -} WASHINGTON {- dot -} EDU
Date: 2008-06-03

Hi Sajid,

congratulations to your nice looking crystals. I'm not sure if someone
already sugested to mount smaller crystals ?
You write they need 4-5 days, I assume you can already see them earlier
before they reach that size. Am I roughly right in the assumption that
these crystals are about 50-70 x 50-70 x 800 micrometers ?
At what part of the crystal do you shoot after having mounted it ?
Are you using a loop which would fit the crystal or a smaller loop ?
If using a smaller loop try shooting at parts of the crystal which are
within the loop and check the part that sticks out of the loop. Try to
reduce the beamsize to the size of the crystal.
Since you know that glycerol is good, try adding other cryo-protectants
in combination e.g. MPD, EG or small PEGs

Good luck,

Juergen

sajid akthar wrote:

>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/
>
>
> ------------------------------------------------------------------------
>

--
Jürgen Bosch
University of Washington
Dept. of Biochemistry, K-426
1705 NE Pacific Street
Seattle, WA 98195
Box 357742
Phone: +1-206-616-4510
FAX: +1-206-685-7002
Web: http://faculty.washington.edu/jbosch

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CCP4bb <-- 2008 <-- June 2008 <-- 03 June 2008

Previous message:
Subject: Re: mosaicity,was:crystallisation
From: Tommi Kajander tommi {- dot -} kajander {- at -} HELSINKI {- dot -} FI
Date: 2008-06-03

Next message:
Subject: Re: crystallisation
From: Kay Diederichs kay {- dot -} diederichs {- at -} UNI-KONSTANZ {- dot -} DE
Date: 2008-06-03