MICROGRAVITY PROTEIN CRYSTALLIZATION ABOARD THE PHOTON SATELLITE

Human immunodeficiency virus (HIV) reverse transcriptase was used as a sample protein to determine whether the optimum conditions for crysta llisation in microgravity were identical to those on Earth. The degree of reproducibility of the results in microgravity was also tested. Th e results showed that; comparing experiments performed in identical ap paratus, the conditions for obtaining the largest crystals in microgra vity were different from the optimal conditions on Earth. Crystal form , size, visual quality and the reproducibility of the results were no different from those on Earth. Crystallisation took place in the vapou r diffusion set-up of the Russian Kashtan apparatus which flew on a Ph oton satellite (4-20 October 1991).