The Advanced Protein Crystallization Facility (APCF) was an Italian Space Agency (ASI) facility that supported a series of investigations focused on growing protein crystals in microgravity. Several investigators collaborated on the APCF, contributing samples and evaluating the facility for crystal growth in microgravity.Facility Manager(s)
Astrium GmbH, Immenstaad, , Germany
National Aeronautics and Space Administration (NASA)Expeditions Assigned
3Previous ISS Missions
The Advanced Protein Crystallization Facility flew on several space shuttle flights, beginning in 1985.
In the Advanced Protein Crystallization Facility (APCF), crystal growth was initiated by causing a protein solution to supersaturate (a condition where there is more protein than can be dissolved in the volume of fluid). As a result of this supersaturation, the protein crystals fell out of solution and began to grow. Supersaturation was achieved by allowing water to be diffused out of the protein solution or by introducing precipitant into the solution, thereby decreasing the solubility of the protein. The APCF was the first facility to use three methods of protein crystal growth: liquid-liquid diffusion, vapor diffusion, and dialysis. During liquid-liquid diffusion, the protein solution, a buffer solution, and a precipitant solution were initially separated by shutters. When the shutters were removed, the precipitant solution diffused through the central buffer solution into the protein solution, causing the protein to become less soluble and initiating crystal growth. In the vapor diffusion method, a crystal formed in a protein solution as a precipitant drew moisture from a surrounding reservoir. In the dialysis method, salt drew moisture away from the protein solution via a membrane separating the two, forming crystals.
Each APCF unit accommodated 48 modular protein crystal growth chambers, or reactors, of which 10 could be observed by a high-resolution video camera. The hardware consisted of a process chamber, power and data electronics, camera electronics, an optical and video system, a thermal control system, and a tape recorder.
The Advanced Protein Crystallization Facility (APCF) reactors were filled in Europe and shipped to the Kennedy Space Center, Cape Canaveral, Florida, 10 days before launch. The reactors were activated after their transfer to EXpedite the PRocessing of Experiments to Space Station (EXPRESS) Rack 1 on the International Space Station. The facility's processing chamber was maintained at 20 °C, and temperature data were recorded throughout the mission. Camera images in black and white were digitized and stored on the facility tape recorder. Data electronics recorded and stored other information.
On return to Earth, the protein crystals produced in the APCF were examined using crystallography, and computers made the mathematical calculations needed to enable three-dimensional modeling of the proteins' structures.
The initial analysis of crystals returned from the Advanced Protein Crystallization Facility indicated that the hardware performed as expected and produced high-quality protein crystals for analysis by the investigator teams.