Re: [ccp4bb] cracking crystal

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

Previous message:
Subject: Re: space groups not supported by Refmac5
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2009-09-01

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Subject: Off-topic: Carba-NAD
From: Antony Oliver antony {- dot -} oliver {- at -} ICR {- dot -} AC {- dot -} UK
Date: 2009-09-01

Subject: Re: cracking crystal
From: Roger Rowlett rrowlett {- at -} COLGATE {- dot -} EDU
Date: 2009-09-01

We have had very good success with fragile,
crack-prone crystals by doing gradual soaks in increasing glucose.
Besides the osmotic pressure/solvent composition changes induced by
cryopreservation, another reason crystals crack is drop dehydration.
You can minimize dehydration of exposed drops by carrying out transfers
in the cold room (I hate that, but it sometimes works), or by replacing
coverslips over the well to maintain humidity.

The most gentle method we use is our "no-fail" cryoprotection procotol,
which you can find at:

http://capsicum.colgate.edu/chwiki/tiki-index.php?page=Mounting+Protein+Crystals#No_fail_cryoprotection

We have successfuly cryopreserved crystals that could not be frozen any
other way.

Fengxia Liu wrote:
cite="mid:6104e0f30909010325n44cb5eb1x9d78f8b38eb1baa1@mail.gmail.com"
type="cite">

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

Roger S. Rowlett

Professor

Department of Chemistry

Colgate University

13 Oak Drive

Hamilton, NY 13346

tel: (315)-228-7245

ofc: (315)-228-7395

fax: (315)-228-7935

email: rrowlett@colgate.edu

CCP4bb navigation

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

Previous message:
Subject: Re: space groups not supported by Refmac5
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2009-09-01

Next message:
Subject: Off-topic: Carba-NAD
From: Antony Oliver antony {- dot -} oliver {- at -} ICR {- dot -} AC {- dot -} UK
Date: 2009-09-01