Physical aspects of protein crystal growth investigated with the Advanced Protein Crystallization Facility in reduced-gravity environments

The physicochemical aspects of protein crystallization in reduced-gravity environments (µg) have been investigated with the Advanced Protein Crystallization Facility during six space missions. This review summarizes the results, dealing with the mechanisms of nucleation and crystal growth and with the quality of the crystals that were obtained under reduced gravity as well as under normal gravity on earth. Statistical analyses of the experimental data strongly support the fact that µg has a positive effect on crystallization and on crystal quality. A comparison of experiments and theories of protein crystallization in reduced-gravity environments is presented. Recommendations for improving the performance of protein crystallization experiments in µg and on earth are discussed.