Microgravity, crystallization

F. Otalora, J. M. Garcia-Ruiz. Crystal growth studies in microgravity with the APCF. I. Computer simulation of transport dynamics. J Cryst Growth 752 141, 1997. 

Figure 7.10 (a) Double-axis rocking curve of a microgravity-grown GaAs crystal after heater failure, (b) Equivalent triple-axis reciprocal space map CuK 004... 

The crystals of NCPs containing a-satellite DNA palindrome and chicken erythrocyte histones diffracted isotropically to 3.0 A using an in-house rotating anode X-ray source and to better than 2.5 A at a moderate intensity synchrotron beamline [30,31]. The crystals used for structure determination were grown in the microgravity environment using a counter-diffusion apparatus [32]. Ground-based... 

The 46-residue protein crambin has been solved at 0.83 A resolution at 130 K.6 Some proteins have been crystallized in microgravity in space rockets where the convection-free conditions can produce larger and better crystals. RNase A crystals grown in microgravity diffracted x-rays to 1.06 A resolution, approximately 0.2 A higher resolution than previously observed in terrestrially grown RNase A crystals.7 At these very high resolutions, alternate conformations of some side chains may even be seen. 

In 1996, Dr. Ozin demonstrated the self-assembly of crystals with a porous structure in space, under the conditions (such as microgravity) found aboard a Space Shuttle. Since then, he has shown how the self-assembly of many materials can be controlled to produce their structure. 

Wang, Y. P., et al., Protein crystal growth in microgravity using a liquid/liquid diffusion method. Micrograv. Sci. Technol. 1996, 9 (4), 281-283. 

Miller, T. Y., He, X.M., Carter, D.C., A comparison between protein crystals grown with vapor diffusion methods in microgravity and protein crystals using a gel liquid liquid diffusion ground-based method. J. Cryst. Growth 1992, 122 (1-4), 306-309. 

Thomas, B. R., et al.. Distribution coefficients of protein impurities in ferritin and lysozyme crystals - Self-purification in microgravity. J. Cryst. Growth 2000,... 

Density gradients are established at several stages in the crystallization process (Fig. 5). As molecules attach to the growing crystal surface, the solution near the crystal is depleted of solute and becomes less dense than the bulk solution. Under the influence of gravity, such density differences result in convection currents. However, in microgravity, solutions with different densities are not subject to convection, so that solutions mix with less turbulence (Littke and John, 1984) and equilibration between solutions is much slower (DeLucas et al., 1986). 

Littke, W., and John, C. Protein single crystal growth under microgravity. Science 225, 203-204 (1984). 

---