I have to second that.
I recently had crystals that will only grow after seeding and will live
for exactly five days. On the sixth day, the same drop will have tracks
of dissolved crystals left in every drop: they almost look like tire
tracks. The crystals frozen on the fifth day diffract to 2.2 A, and I
phased with these crystals using Se-Met, so they were definitely good on
the fifth day. In this case, the structure did show why the crystals
were so unstable, a whole domain (40% of the protein) was swerving
several degrees without much crystal contacts holding it down. Actually,
there was almost no crystal contacts in one dimension: these crystals
should not have formed!
So aging may be good until a certain day, and then it can turn really
badly after that.
Engin
Edward A. Berry wrote:
For a counterexample, from Iwata's group,
Horsefield et al. Succinate: quinone oxidoreductase Acta.
Cryst.(2003). D59, 600-602:
"It proved critical to freeze the crystals within 72 h of
crystallization set-up. Crystals that were frozen after this time
limit showed no diffraction. This alteration in properties was
apparent by the change in colour from deep orange to pale yellow that
was observed in crystals more than four weeks old (Fig. 1c). The deep
orange colour of the crystals is attributed to the presence of haem b
within the protein. The loss or breakdown of haem, demonstrated by the
change of colour in the crystals, could lead to structural instability
and consequently loss of diffraction. "
I've heard the Fe-S clusters of E. coli SDH are oxygen-sensitive in
the isolated enzyme.
The mitochondrial counterpart is more stable, we've collected data
from crystals 1-2 years old,
and seen "conversion" (new crystals grow while old crystals dissolve)
to a new space group
with better diffraction (that was a within few months after setup).
Edward Snell wrote:
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Dear All,
I was recently trying to find references on how age may degrade a
crystal, i.e. grow them and use them or preserve them as fresh as
possible. I seem to remember seeing a couple of papers on this but my
memory is fading and I have been unable to locate them. Can anyone jog
my memory or tell me if I'm imagining things? I've found plenty on the
protein prep etc. but nothing on the crystal.
Thanks,
Eddie.
Edward Snell Ph.D.
Assistant Prof. Department of Structural Biology, SUNY Buffalo,
Hauptman-Woodward Medical Research Institute
700 Ellicott Street, Buffalo, NY 14203-1102
Phone: (716) 898 8631 Fax: (716) 898 8660
Email: esn...@hwi.buffalo.edu Telepathy: 42.2 GHz
Heisenberg was probably here! Crystallization, how quaint!
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