I third it - we used 3.2M + 5% glycerol ammonium sulfate to
cryoprotect crystals grown in 1.2M ammonium suphate (Bayliss et al.
JBC 2002). This really helped diffraction too. My tip when handling
drops at very high salt is to make a little circle of wet tissue paper
around your coverslip to make a humidity chamber. You'll have much
longer to fish crystals out of the drop before salt crystals start to
form.
Good luck
Richard
================
Dr Richard Bayliss
Royal Society University Research Fellow
& Career Development Team Leader
Section of Structural Biology
Institute of Cancer Research
237 Fulham Road
London SW3 6JB
UK
Tel: +44 (0)20 71535557
Fax: +44 (0)20 71535457
On 19 Aug 2009, at 7:20 PM, James Holton wrote:
> I second that one. Ammonium sulfate is one of my favorite cryos. I
> recommend making up a saturated solution of ammonium sulfate, as it
> is actually a very good cryo all by itself, and then "dilute" it by
> adding the rest of the stuff in your condition (buffers, etc. and a
> little bit of water). You want to be a little below saturation so
> that the salt does not grow crystals of its own while you are
> soaking. This is especially important if your protein crystals are
> hexagonal rods!
>
> -James Holton
> MAD Scientist
>
> Savvas Savvides wrote:
>> Hi Brenda
>> Try > 3M ammonium sulfate itself! We have tried that with great
>> succes by
>> cryo-cooling xtals grown at 3.2M AS straight out of their
>> crystallization
>> drops. You can consult the "M&M" section in Kyndt J. et al
>> Biochemistry 2007
>> Jan 9;46(1):95-105 for a more detailed description of what we did.
>>
>> Best of luck
>> Savvas
>>
>> ---- Savvas Savvides L-ProBE, Unit for Structural Biology Ghent
>> University K.L. Ledeganckstraat 35 9000 Ghent, BELGIUM office: +32-
>> (0)9-264.51.24 ; mobile: +32-(0)472-92.85.19 Email: [log in to unmask]
>> http://www.lprobe.ugent.be/xray.html
>>
>>
>>
>> -----Original Message-----
>> From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of
>> Schulman, Brenda
>> Sent: Wednesday, August 19, 2009 6:19 PM
>> To: [log in to unmask]
>> Subject: [ccp4bb] Cryoprotection in > 3M ammonium sulfate
>>
>> Hello!
>>
>> I would be grateful for suggestions on cryoprotectants for crystals
>> growing
>> in > 3M ammonium sulfate.
>>
>> Thanks!
>>
>> Brenda
>>
>>
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