Theresa,
A little off from the original question.
You should have started a new thread.
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 <[email protected]>
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
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http://www.chem.gla.ac.uk/protein/mirror/stura/index2.html
e-mail: [email protected] Fax: 33 (0)1 69 08 90 71
