Harry
Can you clarify why you get "a substantially better structure at cryo
temperatures"
e.g higher intensity at high resolution due to reduction in B factors,
reduction in radiation damage, anything else?
Colin
-----Original Message-----
From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On
Behalf Of harry powell
Sent: 19 June 2008 10:12
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] is it Ok to freeze
Hi
If you mean organic small molecules, then the opinion for the
last 15 years at least is probably "yes, unless you know you'll have a
phase change".
Most small molecule crystals don't have the same problems with
needing cryoprotectants as macromolecules, due in large part to not
having a large proportion of water in the lattice, so the process is
somewhat more straightforward. Also, most small molecule crystals can be
handled quite happily in the absence of mother liquor, and you don't
have to worry about them drying out while transferring to the fibre
(rather than loop) which would normally be used for mounting them. Of
course, there are numerous exceptions to the "most" I'm referring to
here.
In most cases you'll get a substantially better structure at
cryo temperatures (of course, what "better" means may be open to
debate).
On 19 Jun 2008, at 09:47, Jayashankar wrote:
Dear Scientists and Friends,
I am not sure, whether organic crystals need to be in
cryo stream necessarily during data collection from an in house
xray machine .
How most of the organic crystals have been solved
mostly?
--
S.Jayashankar
(A bit confused new generation researcher).
Research Student
Institute for Biophysical Chemistry
Hannover Medical School
Germany
Harry
--
Dr Harry Powell, MRC Laboratory of Molecular Biology, MRC
Centre, Hills Road, Cambridge, CB2 2QH
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