Dear Cedric,
Another possible method for RT data collection is the new humidifier
device HC1b developed at the EMBL that is now available for use at the
ESRF (see links below). It works in a very similar way to the FMS but a
little easier to use and can be used at the ESRF with very little
hassle. For availability please contact the ESRF and for technical
information please let me know. My suggestion though for crystals that
move while collecting is to use micromesh loops (either MiTeGen or
Molecular Dimensions) instead of using standard loops. If you wick the
mother liquor out once you've mounted them you get lots of contact
points with the crystal and thus less slipping. If you are going to
collect at a synchrotron source you may also want to reduce your flux
(attenuating) and only use one pass so that your exposure time will be
increased and thus your angular speed when collecting will be slower
avoiding movement.
But no matter what you do you may still get some slipping, you simply
cannot fully avoid it totally when working at RT. So you may have to
take a wedge of good frames and scale separately from other wedges and
then merge everything together. You should also tell your processing
software to correct for slippage to get better scaling. Furthermore, you
may just have to collect different crystals take the best bits and merge
it all together; this is something that you may have to do anyway
considering radiation damage at this temperatures.
Link http://www.esrf.fr/UsersAndScience/Experiments/MX/special-setup
I hope this helps,
Regards,
Juan
cedric bauvois wrote:
Dear CCP4ers,
in their paper entitled " Using cryoloops for X-ray data collection
from protein crystals at room temperature: A simple applicable method"
( *Journal of Crystal Growth*
<http://www.sciencedirect.com/science/journal/00220248>
Volume 281, Issues 2-4
<http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235302%232005%23997189997%23601824%23FLA%23&_cdi=5302&_pubType=J&view=c&_auth=y&_acct=C000026678&_version=1&_urlVersion=0&_userid=532047&md5=9a4e7b2fc158c6d2396925c79d995e3d>,
1 August 2005, Pages 592-595.), the authors present a way to mount
crystals using "a cryoloop accompanied by a glass capillary cap" (see
abstract below).
Do you know if any commercial version of such system are now available ?
Abstract: Although cryoloops are now routinely used for X-ray data
collection from protein crystals in cryocooling condition, it is still
necessary to collect X-ray diffraction data from protein crystals at
room temperature under such circumstances as to find resolution limit
and/or to avoid damage of protein crystals at cryogenic temperature
(e.g. 100 K). Here, we show that a cryoloop, which is accompanied by a
glass capillary cap to maintain humid environment of crystal in the
cryoloop, can be used not only to examine protein or non-protein
crystals but also to collect X-ray diffraction data for structural
analysis from protein crystals at room temperature. The size of
cryoloop should be carefully chosen so that the crystal does not move
in the cryoloop. This crystal mounting method can be time-saving
compared to the traditional method to mount a crystal in a glass
capillary tube.
Many thanks
--
Dr. Cedric Bauvois
Cristallographie des protéines
Institut de Recherches Microbiologiques JM Wiame -IRMW
Av E. Gryzon 1, 1070 Brussels (Belgium)
tél: +32 (0)2 5273634
fax: +32 (0)2 5267273
--
Juan Sanchez-WEATHERBY
Tel:33 (0) 47620 7266
Website: http://www.embl.fr
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