Crystallization within agarose gel in microgravity improves the quality of thaumatin crystals

Abstract

To prevent crystals from moving in orbit and sedimenting upon their return to earth, the model protein thaumatin was crystallized in agarose gel in the Advanced Protein Crystallization Facility during the eight-day Space Shuttle mission STS-95 (November 1998). The quality of tetragonal crystals grown in microgravity was compared with that of controls prepared in parallel in the laboratory. On the basis of their diffraction properties, microgravity crystals were more ordered than crystals grown in gel on earth (the latter being, on average, better than reference crystals obtained in solution on earth). It is concluded that protein crystallization within a gel in microgravity may yield crystals of superior quality by combining the advantages of both environments. A possible explanation for the positive effect of microgravity on protein crystallization in gels involving the better quality of the nucleus is discussed.

Investigating the Effect of Impurities on Macromolecule Crystal Growth in Microgravity

“…The effects of partitioning may also vary from system to system. For example, Lorber et al 15 report thaumatin crystals of superior and more uniform crystallographic quality in microgravity in comparison to identical ground controls, while finding no significant difference in macromolecular impurities between crystal content and original thaumatin solution. Long et al 41 also report that microgravity-grown crystals of insulin diffracted with higher intensity and to higher resolution with no significant difference in the physical, biochemical, or biological characteristics of the insulin preparation.…”

“…13,16 Impurities structurally similar to the macromolecule of interest are more likely to be incorporated into the crystal in significant quantities. [15][16][17] This may result in significant changes in crystal morphology due to slower growth on one crystal face relative to another, which results in a shortening 17,18 or lengthening of the crystal 19 in comparison to those grown in pure solutions.…”

Femtosecond laser processing of protein crystals grown in agarose gel

“…Agarose gel can be utilized by several conventional crystallization techniques [14,15], and the gel-grown crystals have clear advantages for protein crystallography. Gel media reduce convection and prevent crystal sedimentation, resulting in the 20µm 500µm Fig.…”

Promising approaches to crystallization of macromolecules suppressing the convective mass transport to the growing crystal

“…42 It should be noted that the crystallization in hydrogel can be implemented under microgravity conditions. 49 This approach makes it possible to avoid convection currents and the sinking of the crystals to the bottom during the descent and landing of a spacecraft.…”