Pius,
The situation you describe is an off-equilibrium situation. You have
applied a perturbation
and that may not be reversible!
Enrico.
On Wed, 08 Feb 2012 16:35:56 +0100, Pius Padayatti <ppadaya...@gmail.com>
wrote:
Hi Enricho,
The scenario of streak seeding follows Ostwald ripening but will
this happen in other situations as follows
But in a special case where you have some crystals that appear as large
rods which dissolved when taken out of the incubator (or) during the
observation( these were antibody-complex crystals which were grown in
bicelles(DMPC:CHAPSO
and detergent mixtures and cholestrol, conditions citric acid pH 4.5,
with 2.4 M ammonium sulfate).
The crystals re-apparered in a day over noght incuabtion as heavy
showers of needles with heavy precipitate around.
Very hard to reproduce the conditions.
Still trying to work around these conditions.
Would like to know your thoughts if this is against the laws small
crystals to large crystals (energetically
favoured) conditions.
Also any suggestions welcome for improvements.
Pius
The answer to your question is very simple. Small crystals will
dissolve
when the degree of saturation
of the solution becomes too low to support their relatively high
surface to
volume ratio.
The larger crystals will still continue to grow because of their higher
surface/volume ratio but will do so slowly.
I have achieved the dissolving of small crystals in favour of large ones
only once with 10 µl drops.
While it is difficult to achieve this with spontaneously nucleated
crystals,
with seeding thing are very different.
This phenomenon is an every day observation if you use streak seeding on
drops that have been
equilibrated for different amount of time against different
concentrations
of precipitant and you can
also add an additional variable by using different ratios of protein to
precipitant in the drop.
The goal is to seed at a low degree of superstauration. The small seeds
will
be visible along the streak
immediately after seeding. When you look later on you will see only the
bigger crystals.
Streak seeding is great if you want to play this game.
Enrico.
On Wed, 08 Feb 2012 12:08:23 +0100, Theresa H. Hsu
<theresah...@live.com>
wrote:
A little off from the original question. Why don't small crystals
dissolve
to make a bigger crystal, especially when the small ones grow on top
of each
other? Can the clustered 3D crystals (I think it is called macroscopic
twin)
be used for full data collection?
Again, thank you.
Theresa
--
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
LTMB, SIMOPRO, IBiTec-S, CE Saclay, 91191 Gif-sur-Yvette, FRANCE
http://www-dsv.cea.fr/en/institutes/institute-of-biology-and-technology-saclay-ibitec-s/unites-de-recherche/department-of-molecular-engineering-of-proteins-simopro/molecular-toxinology-and-biotechnology-laboratory-ltmb/crystallogenesis-e.-stura
http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html
e-mail: est...@cea.fr Fax: 33 (0)1 69 08 90
71
--
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
LTMB, SIMOPRO, IBiTec-S, CE Saclay, 91191 Gif-sur-Yvette, FRANCE
http://www-dsv.cea.fr/en/institutes/institute-of-biology-and-technology-saclay-ibitec-s/unites-de-recherche/department-of-molecular-engineering-of-proteins-simopro/molecular-toxinology-and-biotechnology-laboratory-ltmb/crystallogenesis-e.-stura
http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html
e-mail: est...@cea.fr Fax: 33 (0)1 69 08 90 71
