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 -- Pius S Padayatti,PhD, Phone: 216-658-4528
