Dear all,
Thermal motion reduction and lower radiation damage are reasons for
improved data associated
with low temperature data collection. The liquid to glass transition of
the solvent allows us to
have a better idea of the hydration shell around the protein. This is
something that room temperature
data collection with current techniques does not allow. There can be valid
biological reasons to purse
RT data collection (without the aim to achieve higher resolution that with
cryo methods).
Historically, the transition from routine RT data collection to 100K was
quite painful at the start, but now we think
nothing of it. Every case that presents a new challenge is an opportunity
to improve our techniques.
But my comment was more related to the idea that with a better
undertsanding of the physical parameters
that allow crystal formation and stabilization we can find a way to
collect better data on our current and future
crystals.
Post-crystallization interventions (dehydration, soaking in various
compounds annealing, etc.)
have been used to improve diffraction. The room temperature result are
important to define
the starting point, from here the we have the challenge to find out how to
improve the crystal
and the data that can be extracted from it.
I accept a biological interest in also collecting RT data, but to achieve
higher resolution data,
low temperature has many advantages. I hope my comment is clearer now,
Enrico.
Tim
On 02/06/2014 12:50 PM, James Foadi wrote:
Dear Enrico,
"almost always it will be possible to achieve better diffraction
using cryogenic data collection."
I would say "almost always until now". Times change,
instrumentation improves and data collection techniques are
becoming cunning. It's right time people start exploring the new
possibilities offered by modern synchrotrons.
All the best,
J
Dr James Foadi PhD Membrane Protein Laboratory Diamond Light Source
Ltd. Diamond House Harwell Science and Innovation Campus Didcot
Oxfordshire OX11 0DE United Kingdom
office email: james.fo...@diamond.ac.uk alternative email:
j.fo...@imperial.ac.uk
personal web page: http://www.jfoadi.me.uk
On Thursday, 6 February 2014, 11:35, Enrico Stura <est...@cea.fr>
wrote:
Dear Joern and other BBers,
While I fully agree that it is important to test a few images at
room temperature, to know the crystal's potential, I think that
almost always it will be possible to achieve better diffraction
using cryogenic data collection. Those rare cases, as the one you
mention below are worthy of critical investigation as to why there
is a loss of order on cryo-cooling: Unsuitable cryoprotectant is my
first guess. The rate of cooling in liquid N2 is slow, liquid
ethane could be a better choice.
Enrico
On Thu, 06 Feb 2014 11:19:47 +0100, Joern Krausze
<jk...@helmholtz-hzi.de> wrote:
Dear Theresa,
We recently collected a room temperature data set from one single
crystal at Petra III. The beam line was equipped with a Pilatus
detector. Data were good to 2.7 A. In contrast, at 100 K similar
crystals diffracted very poorly. So, it is perfectly possible to
obtain useful room temperature data sets from synchrotron
sources. I have to admit that in our case it certainly helped
that the crystal belonged to a high-symmetry space and full
completeness was achieved after 40 degrees angular range.
Regards,
Joern
Sent from my iPad
On 06.02.2014, at 10:51, Theresa Hsu <theresah...@live.com>
wrote:
Dear crystallographers
Just out of curiosity, is it possible to collect datasets from
crystals at room temperature at synchrotron? Are fast detectors
like Pilatus useful for this?
Thank you.
Theresa
- --
- --
Dr Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen
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--
Enrico A. Stura D.Phil. (Oxon) , Tel: 33 (0)1 69 08 4302 Office
Room 19, Bat.152, Tel: 33 (0)1 69 08 9449 Lab
http://www-dsv.cea.fr/ibitecs/simopro/ltmb/cristallogenese
LTMB, SIMOPRO, IBiTec-S, CE Saclay, 91191 Gif-sur-Yvette, FRANCE
http://scholar.google.com/citations?hl=en&user=Kvm06WIoPAsC&pagesize=100&sortby=pubdate
http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html
e-mail: est...@cea.fr Fax: 33 (0)1 69 08 90 71
