CRYSTALLIZATION OF APOCRUSTACYANIN C-1 ON THE INTERNATIONAL MICROGRAVITY LABORATORY (IML-2) MISSION

Rod-shaped crystals of apocrustacyanin C1 have been grown under microg ravity on the International Microgravity Laboratory (IML-2) NASA space shuttle mission using the vapour-diffusion set-up of the Advanced Pro tein Crystallization Facility (APCF). The crystals obtained under micr ogravity are compared with crystals grown simultaneously in ground con trol experiments in identical APCF reactors, and with those obtained i n the laboratory. The degree of reproducibility of the results in micr ogravity was also tested. Statistically, the microgravity-grown crysta ls are larger and of better X-ray diffraction quality than those grown in the ground controls but inferior to the best crystals grown in sit ting drops, in the laboratory. Diffracting crystals, the best to 2.3 A ngstrom, were produced in seven out of the eight reactors in micrograv ity, whereas the eight ground control reactors yielded only one poorly formed crystal suitable for diffraction studies, which also diffracte d to 2.3 Angstrom. The crystals belong to the space group P2(1)2(1)2(1 ) With two subunits per asymmetric unit.