Re: [ccp4bb] cracking crystal

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

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Subject: Re: cracking crystal
From: Jim Pflugrath Jim {- dot -} Pflugrath {- at -} RIGAKU {- dot -} COM
Date: 2009-09-01

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Subject: Re: cracking crystal
From: Kris Tesh Kris {- dot -} Tesh {- at -} RIGAKU {- dot -} COM
Date: 2009-09-01

...and I prefer to use PFPE (perfluoropolyether, trade name FOMBLIN) as an
oil since it is less viscous, has no reactivity and is a low temp
lubricant that freezes easily. Small molecule crystallographers have used
it for years.

Kris
---------------------------------
Kris F. Tesh, Ph D
Director, Macromolecular Products
Rigaku Americas Corporation
9009 New Trails Drive
The Woodlands, TX 77381 USA
001 281 362 2300 x 144

From:
Leonard Thomas
To:
CCP4BB@JISCMAIL.AC.UK
Date:
09/01/2009 10:09 AM
Subject:
Re: [ccp4bb] cracking crystal

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: cracking crystal
From: Jim Pflugrath Jim {- dot -} Pflugrath {- at -} RIGAKU {- dot -} COM
Date: 2009-09-01

Next message:
Subject: Re: CNS to PDB format conversion
From: Manoj Saxena mks131 {- at -} REDIFFMAIL {- dot -} COM
Date: 2009-09-01