Experiments in microgravity: a comparison of crystals of a carbohydrate-binding fab grown on the ground, on space shuttle Discovery and on space station Mir.

The Fab fragment of the hybridoma antibody (YsT9.1) specific to Brucella abortus has been crystallized on earth using both Linbro plates and ground-based models of the flight hardware, as well as in microgravity on board the space shuttle Discovery and the space station Mir. Large-scale experiments using Linbro plates gave two different crystal morphologies, pyramidal and rhomboid, depending on conditions. The pyramidal crystals proved to scatter X-rays to higher resolution, and conditions within the ground-based flight hardware for both Discovery and Mir were adjusted to produce crystals with this morphology. The experiment on Discovery produced large crystals in each of ten chambers. The experiment on Mir produced crystals in only one of the five assigned chambers, despite the fact that the simultaneous ground-based experiment produced large crystals in every corresponding chamber. Data collection was attempted for crystals from both space and ground-based experiments. Higher resolution data was obtained from crystals grown on Discovery than from either Mir or ground-based crystals, even though the crystals obtained from Discovery were smaller and forced to grow over a much shorter period of time because of the shorter length of the shuttle mission.