[ccp4bb] Questions about cryoprotectant

- Protein crystallography

Main steps:

- Protein purification
- Crystallisation

Special:

- Programs for crystallography
- X-ray detectors

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   - Protein
   - Peptide
   - Amino Acids

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

Previous message:
Subject: Re: gpp4 version 1.2 released
From: Morten Kjeldgaard mok {- at -} BIOXRAY {- dot -} AU {- dot -} DK
Date: 2009-10-07

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Subject: Re: Questions about cryoprotectant
From: Roger Rowlett rrowlett {- at -} COLGATE {- dot -} EDU
Date: 2009-10-07

Subject: Questions about cryoprotectant
From: ycheng ycheng {- at -} EMAIL {- dot -} UNC {- dot -} EDU
Date: 2009-10-07

Hi,
I am trying to find an appropriate cryo-condition for my protein crystals.
The mother liquid is 2-2.5M Ammonium phosphate dibasic
100mM TrisHCL pH8. The room-temperature diffraction looks not bad
(mosaicity 0.8, resolution 2.6) But the diffraction turned to be very
mosaic if I freeze the crytals in the absence of cryos or in the presence
of mother liquid plus different concentration of glycerol (5%,10%,15%.20%).
I don't think the ice formation is the problem since I didn't see any ice
by my eyes or ice diffraction in the presence or absence of cryos. Also, I
didn't see any cracks on my crystals when I transfered them to the cryo
conditions I have already tried.
My question here is:
1)what's the role of cryo? I know it helps prevent ice formation. Based on
my case, it looks like cryo might also help to keep the crytal packing good
when frozed.
2) What do I need to do to find a good cryo? What in my mind is to try
other cryos like sucrose, PEG400, ethylene glycol.

Thanks a lot for your attention!

Yuan

CCP4bb navigation

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

Previous message:
Subject: Re: gpp4 version 1.2 released
From: Morten Kjeldgaard mok {- at -} BIOXRAY {- dot -} AU {- dot -} DK
Date: 2009-10-07

Next message:
Subject: Re: Questions about cryoprotectant
From: Roger Rowlett rrowlett {- at -} COLGATE {- dot -} EDU
Date: 2009-10-07