Hi
Without wishing to start an argument, I've been checking with some of
my colleagues who are chemical crystallographers - the reply I get is
that, for routine structural analysis, "pretty well all datasets are
collected at 100K unless the crystals fall apart at low T, or if the
cryostream is broken".
I should point out that the first production Cryostream that I came
across (serial number 2, which I think may have been the first one
sold!) was in the Cambridge Department of Chemistry in about 1985.
They didn't become common until the mid-1990's in PX labs, when they
were already well-established as a bit of pretty well essential kit
for small molecule work.
So although what Remy says is true, the practice is to cryocool most
of the time.
On 19 Jun 2008, at 12:08, Remy Loris wrote:
Typically crystals of small organic compounds do not require
freezing as there are no solvent channels. They do in general not
suffer from radiation damage at room temperature the way protein
crystals do. Occasionally they are mounted in a capillary instead
of simply glueing them to a goniometer if they are air sensitive.
In principle freezing should not damage the crystals, but one still
may have to be carefull if the crystals are large. I think you risk
increasing mosiacity, and any manipulation that is not needed will
on average only reduce the quality of the specimen rather than
improve it
Remy Loris
Vrije Univesiteit Brussel
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
