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
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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: savvas.savvi...@ugent.be
http://www.lprobe.ugent.be/xray.html
-----Original Message-----
From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of
Schulman, Brenda
Sent: Wednesday, August 19, 2009 6:19 PM
To: CCP4BB@JISCMAIL.AC.UK
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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