Re: [ccp4bb] crystallisation

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Subject: Re: crystallisation
From: Clemens Vonrhein vonrhein {- at -} GLOBALPHASING {- dot -} COM
Date: 2008-06-03

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

Subject: Re: crystallisation
From: "Green, Todd" green {- at -} CBSE {- dot -} UAB {- dot -} EDU
Date: 2008-06-03

Hello Sajid,

Is you crystal this mosaic in all three directions? It could be that with the longer rods, that your mosaicity is high in one direction but not so much in the other two directions. In this case I'd guess shooting down the length of the xtal might result in increased mosaicity. Thus the way you orient the crystal when shooting it, may help. We have had this type of problem before and overcame it by orienting the crystals when we looped them up in order to avoid shooting parallel with the long part of the crystal. Of course, this all comes back to whether the mosaicity is anisotropic.

Good Luck -
Todd

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

_______________________________________________________________________

Dr. Christian Biertümpfel
Laboratory of Molecular Biology

NIDDK/National Institutes of Health phone: +1 301 402 4647
9000 Rockville Pike, Bldg. 5, Rm. B1-03 fax: +1 301 496 0201
Bethesda, MD 20892-0580
USA
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CCP4bb <-- 2008 <-- June 2008 <-- 03 June 2008

Previous message:
Subject: Re: crystallisation
From: Clemens Vonrhein vonrhein {- at -} GLOBALPHASING {- dot -} COM
Date: 2008-06-03

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