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 <[log in to unmask]>
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
>> <[log in to unmask]>
>> 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: [log in to unmask] 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: [log in to unmask] Fax: 33 (0)1 69 08 90 71
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