Re: [ccp4bb] cracking crystal

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: CNS to PDB format conversion
From: Roger Rowlett rrowlett {- at -} COLGATE {- dot -} EDU
Date: 2009-09-01

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Subject: Re: anisotropic diffraction in refinement
From: Pavel Afonine PAfonine {- at -} LBL {- dot -} GOV
Date: 2009-09-01

Subject: Re: cracking crystal
From: Leonard Thomas lmthomas {- at -} OU {- dot -} EDU
Date: 2009-09-01

One thing that I have had work in the past is just increase the
percentage of PEG. I think something around 30-35% may work for
PEG4K, maybe a little higher. Most PEGS will work as a cryo
protectant if the concentration is high enough.

Also as mentioned before you could try stepping up the glycerol
concentration very gradually. I had a colleague who said the protein
he worked on in grad school had to be stepped up 1% increments or it
would crack and fall apart. IIRC he had better then 2.0 ang. data for
the final structure.

Leonard Thomas Ph.D.
Macromolecular Crystallography Laboratory Manager
University of Oklahoma
Department of Chemistry and Biochemistry
620 Parrington Oval
Norman, OK 73019

lmthomas@ou.edu
http://barlywine.chem.ou.edu
Office: (405)325-1126
Lab: (405)325-7571

On Sep 1, 2009, at 5:25 AM, Fengxia Liu wrote:

> Dear All,
>
> Could you please help me solve this problem?
>
> I have a sensitive crystal, the mother liquor is 10% PEG4k+ 100 mM
> Tris-buffer pH 8.5, crystal is big and good but very sensitive, when
> i put it in cryoprotectants, cracking happened. First i used
> artificial mother liquor + 25% v/v glycerol, slowly decrease to +
> 12.5% v/v glycerol, all crystals cracked after immersed, finally i
> tried 50% mineral oil + 50% paratone, it still cracked (4- 5 cracks,
> but not broken) . even this cracked crystal can give me 3.2 angstrom
> diffraction, so no cracked crystal might give me 2.0+ angstrom
> diffraction. Now i don't have many crystals to try so many
> cryoprotectants, so anybody has experience on this? any suggestion
> would be greatly appreciated.
>
> Thank you.
> Fengxiale

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: CNS to PDB format conversion
From: Roger Rowlett rrowlett {- at -} COLGATE {- dot -} EDU
Date: 2009-09-01

Next message:
Subject: Re: anisotropic diffraction in refinement
From: Pavel Afonine PAfonine {- at -} LBL {- dot -} GOV
Date: 2009-09-01