scientists gain detailed knowledge of the atomic, 3-D structure of many important protein
molecules used in pharmaceutical research for cancer treatments, stroke prevention, and other
diseases. The knowledge gained could be instrumental in the design and testing of new drugs.
SPACE BENEFITS
The crystals grown in microgravity are able to grow larger and more organized than those
grown on Earth. The results from this investigation may further human space exploration
efforts by creating technological and biological advancements as a direct result from this
research.
RESULTS
Initial analysis of crystals returned from station support the findings of earlier APCF flights:
comparative crystallographic analysis indicates that space-grown crystals are superior in every
way to control-group crystals grown on Earth under identical conditions (except the critical
space environment). Crystals grown in microgravity generally have improved morphology,
larger volume, higher diffraction limit, and lower mosaicity as compared to Earth-grown
crystals. The researchers reported that the electron-density maps calculated from diffraction
data contained considerably more detail, allowing them to produce more accurate 3-D models
(Vergara 2005).
The APCF hardware performed well during International Space Station (ISS) Expedition 3 with
very few anomalies. APCF-Camelids, APCF-Crystal Quality, APCF-Growth, APCF-Lysozyme, APCF-
Octarellins and APCF-PPG10 all produced excellent quality crystals that had better resolution
and other optical properties than those
grown on Earth. APCF-Lipoprotein
successfully produced crystals, but they
did not achieve the expected level of
resolution. APCF-Rhodopsin had slight
technical problems that prevented the
formation of suitable crystals.
Well-diffracting crystals prepared in
space have 2 purposes: understanding
the gravity-dependent phenomena (such
as nucleation and growth mechanisms)
and structural determination. Each new
high-resolution structure may become
the start of a cascade of investigations to
unravel the complexity of the cellular
events like growth, division,
differentiation, communication, motility,
death, and their role in the development of multicellular organisms. This may accelerate the
structure-based design and redesign of drugs targeting pathogens, diseases, and degenerative
Camelid crystals, complexed with lysozyme, grown in the
Advanced Protein Crystallization Facility during International
Space Station Expedition 3. NASA Johnson Space Center
image.